1.1 Plan of the Element

Following the introduction (Section 1), Section 2, ‘What Is CLIL’, provides a definition of the approach and highlights its varied interpretations across different contexts, such as North America and Europe. This section also offers an overview of the theoretical foundations of CLIL, emphasising its dual focus on integrating language and content learning, along with its core concepts and guiding principles.

Section 3, ‘CLIL Implementation’, explores the origins of the educational approach and its expansion around the globe. It presents examples from Europe, Latin America, and Asia, showcasing the flexibility of the approach in different settings.

Section 4, ‘The Effectiveness of CLIL’, is central to any discussion of CLIL. It provides an overview of detailed studies addressing language use and the impact of CLIL on additional language acquisition, content learning, and first language (L1) development. Two subsections 4.3 and 4.4 further examine the impact of CLIL on stakeholders’ attitudes and motivation, as well as its role in addressing classroom diversity.

Section 5, ‘Pedagogical Approaches to CLIL’, analyses two key components of CLIL practice: translanguaging and multimodality in the classroom. These are presented as valuable methodological and practical resources for both subject and language teachers.

Section 6, ‘Assessment and Teacher Education in CLIL’, explores the role of assessment within the CLIL framework and addresses professional development. It highlights essential training needs for effective CLIL instruction and underscores the importance of raising teacher awareness.

The final section (Section 7), ‘Conclusion and Future Perspectives’, summarises the key points covered throughout the Element and offers insights into future directions for the CLIL approach.

This Element will be of interest to researchers, graduate students, and teacher educators engaged in CLIL, as well as to anyone involved in or curious about multilingual education.

2.1 Definition of CLIL

CLIL is an approach that combines the teaching of academic content with the learning of a foreign or second language (L2).Footnote ² The term originated in Europe in the mid-1990s to describe programmes aimed at improving foreign language (FL) proficiency while simultaneously teaching subject matter.

CLIL is characterised by its dual focus, flexibility, and adaptability to various educational settings. That is why it is often described as an umbrella term for educational contexts where a non-native language is used to teach content subjects, integrating language, and content learning. This encompasses a range of models that can be positioned along a continuum from content-driven to language-driven approaches (Cenoz, Reference Cenoz2015; Dale & Tanner, Reference Dale and Tanner2012; Lyster & Ballinger, Reference Lyster and Ballinger2011).

At one end of the continuum, content-driven, are immersion programmes, such as those traditionally found in Canada, where different subjects are taught in an additional language by content teachers. These range from full immersion, sometimes with 100% of the teaching day, to partial immersion, with a smaller portion of instruction in the additional language. At the other end, the language-led side, are examples such as language classes structured around thematic units, which occur in diverse geographical contexts.

This continuum also corresponds to what are commonly referred to as the strong and weak forms of CLIL: hard CLIL and soft CLIL (Ball, Clegg, & Kelly, Reference Ball, Clegg and Kelly2015; Bentley, Reference 47Bentley2010). According to Ball et al. (Reference Ball, Clegg and Kelly2015), this distinction is often influenced by the type of teacher delivering the instruction. Soft CLIL typically describes approaches led by language teachers, while hard CLIL describes programmes that are more subject oriented, with content teachers delivering subject matter through an additional language.

As shown in Figure 1, various contextual factors influence the different types of CLIL. These factors may include the programme’s objectives (whether content-related or language-related), its type (ranging from total immersion to language-oriented courses), the intensity of instruction (in terms of exposure time), as well as the learners’ age and the language of instruction (e.g. foreign, second, heritage, or minority languages).

Figure 1

The CLIL continuum

Figure 1 Long description

A horizontal continuum illustrating the range of Content and Language Integrated Learning (CLIL) programmes from content-driven to language-led approaches. On the left, the “content-driven” end features immersion programmes, such as those traditionally found in Canada, where subject teachers deliver various academic subjects entirely or mostly in an additional language. This includes full immersion programmes with up to 100% of instruction in the additional language, and partial immersion programmes with a smaller proportion of language instruction. On the right, the “language-led” end shows language classes structured around thematic units, typically led by language teachers in diverse geographic contexts.

The continuum aligns with the distinction between “hard CLIL”, programmes that are subject oriented and delivered by content teachers, and “soft CLIL”, programmes that are language focussed and led by language teachers. Various contextual factors influence where a programme falls on this continuum, including the programme’s objectives (content versus language focus), type (total immersion to language-oriented courses), intensity or exposure time to the additional language, learners’ age, and the kind of additional language involved (foreign, second, heritage, or minority languages). This continuum highlights the diversity and complexity of CLIL implementations worldwide, explaining why its definition can be ambiguous and debated.

(adapted from Ball, 2009 and Lyster & Ballinger, 2011)

This continuum evidences the disparity and variety of programmes that combine language and content across contexts, which probably explains why the definition of CLIL can be ambiguous and has even sparked debate over the years (see, for instance, Cenoz, Genesee, & Gorter, Reference Cenoz, Genesee and Gorter2014 and the response by Dalton-Puffer, Llinares, Lorenzo, & Nikula, Reference Dalton-Puffer, Llinares, Lorenzo and Nikula2014). Nonetheless, there are some common features that can be addressed in order to understand what CLIL is. First, CLIL programmes focus on both subject matter and the language of instruction, aiming to simultaneously improve content comprehension and language proficiency. This dual focus is central to many definitions of the approach, such as the oft-cited one by Coyle, Hood, and Marsh (Reference Coyle, Hood and Marsh2010, p. 1): ‘Content and Language Integrated Learning (CLIL) is a dual-focussed educational approach in which an additional language is used for the learning and teaching of both content and language.’ In their definition, the authors underline the idea of an additional language, which ‘is often a learner’s “foreign language”, but which may also be an L2 or some form of heritage or community language’ (Coyle et al., Reference Coyle, Hood and Marsh2010, p. 1).

The duality present in the Coyle et al. definition also appears in other scholarly definitions. For example, Banegas (Reference Banegas2012, p. 117) defines CLIL as ‘an approach in which various methodologies are used to achieve a dual-focussed form of instruction in language and content.’ Similarly, Dalton-Puffer (Reference Dalton-Puffer, Nikula, Dafouz, Moore and Smit2016, p. 29) states: ‘Content and language integrated learning (CLIL) needs to articulate substantial links between the pedagogies of different subjects like mathematics, history, or economics and the pedagogy of language teaching in order to fulfil its promise of “dual focus”.’ In this statement, Dalton-Puffer underscores that the duality of the approach requires pedagogical connections between content and language teaching, which often requires collaboration between content and language teachers. As discussed in Section 5, this pedagogical enterprise is not always easy to overcome.

The balance between language and content instruction, as well as the nature of the CLIL target language, is among the core features of the approach that have been open to different interpretations (Cenoz et al., Reference Cenoz, Genesee and Gorter2014). In fact, as several authors argue (Cenoz et al., Reference Cenoz, Genesee and Gorter2014; Ruiz de Zarobe, Reference Ruiz de Zarobe2013), CLIL shares essential properties with other content-based programmes, such as Content-Based Instruction (CBI). Cenoz et al. (Reference Cenoz, Genesee and Gorter2014) and Ruiz de Zarobe (Reference Ruiz de Zarobe2013) argue that both CLIL and CBI employ an L2 as the medium of instruction and share similar educational objectives. The preference for one term over the other is often context dependent: CLIL is more frequently used in Europe, Asia, and South America, while CBI is typically preferred in North-American contexts. However, both terms are sometimes used interchangeably. For example, Lyster and Ruiz de Zarobe (Reference 58Lyster and Ruiz de Zarobe2018) and Ruiz de Zarobe and Lyster (Reference Ruiz de Zarobe and Lyster2018) referred to both CLIL and immersion in their discussions on content and language integration in school and higher education settings. More recently, Ballinger, Fielding, and Tedick (Reference Ballinger, Fielding and Tedick2024) used the term content-based instruction to describe content teacher education initiatives across Africa, Asia, Australia, Europe, and North America.

Despite their shared foundations (Cenoz, Reference Cenoz2015), CLIL and CBI do not share the same historicity, understood as the historical and cultural embeddedness of educational practices, nor the same political and contextual backgrounds (Gabillon, Reference Gabillon2020). Therefore, in order to fully understand what CLIL is (and is not), it is crucial to identify its distinctive characteristics and engage with the ongoing debates surrounding its evolution (Hemmi & Banegas, Reference Hemmi, Banegas, Hemmi and Banegas2021). Clear definitions and consistent methodologies are needed to provide a coherent and context-sensitive explanation of CLIL across educational settings. As a highly contextualised approach (Hüttner & Smit, Reference 54Hüttner and Smit2014), CLIL requires locally grounded research and adaptation to specific needs. While implementation and practice can vary considerably, there are core theoretical foundations that support the approach. These will be explored in the following section.

2.2 Theoretical Foundations of CLIL

CLIL is supported by various theoretical frameworks that emphasise the integration of content learning and language acquisition. Among these are Sociocultural Theory, Systemic Functional Linguistics, and Cummins’ framework of BICS (Basic Interpersonal Communication Skills) and CALP (Cognitive Academic Language Proficiency), all of which are supported by research and contribute to understanding the cognitive and linguistic demands of CLIL. While other well-recognised theories from Second Language Acquisition, such as Krashen’s (Reference Krashen1985) Input Hypothesis and Swain’s (Reference Swain, Gass and Madden1985) Output Hypothesis, also offer valuable insights, we have chosen to focus on frameworks that address both cognitive and academic language development, as these play an important role in supporting CLIL learning.

Lev Vygotsky’s Sociocultural Theory (Vygotsky, Reference Vygotsky1978) emphasises the importance of social interaction and cultural context in learning, which is highly relevant to CLIL environments. According to Vygotsky, learning occurs most effectively within the Zone of Proximal Development (ZDP), the space between what learners can do unassisted and what they can do with support from an adult or collaboration with more capable peers. CLIL environments align with this concept, as they often involve collaborative activities and discussions that provide opportunities for learners to engage in meaningful, socially mediated interactions. Furthermore, the use of a foreign language in these interactions can promote deeper cognitive engagement (Coyle et al., Reference Coyle, Hood and Marsh2010).

Related to this is the concept of scaffolding, a term introduced by Bruner in the 1970s and defined as a ‘process that enables a child or novice to solve a problem, carry out a task or achieve a goal which would be beyond his unassisted efforts’ (Wood, Bruner, & Ross, Reference Wood, Bruner and Ross1976, p. 90). Scaffolding is often associated with ZPD and sociocultural theory (Mahan, Reference Mahan2020; Mahan & Ruiz de Zarobe, Reference Mahan, Ruiz de Zarobe, Tajeddin and Farrell2024), as a dynamic practice that encourages progress and gradually allows for greater autonomy on the part of learners. As a sample, the study by Mahan (Reference Mahan2020) investigated how three CLIL teachers supported L2 learners’ performance through scaffolding. Twelve lessons (science, geography, and social studies) were videotaped in an 11th-grade CLIL class. A coding manual (Language Arts Teaching Observation Protocol [PLATO]) was used to identify the scaffolding strategies used by the teachers. The outcomes indicated that CLIL teachers provided scaffolding strategies with which to understand some material. The scaffolding strategies included linking concepts in L1 and L2, defining subject-specific terminology, and using visual aids. In addition, the CLIL teachers developed different scaffolding strategies in natural and social sciences.

Building on this perspective, Hill (Reference Hill2020) showed that applying cognitive linguistics in CLIL contexts enhances L2 learners’ awareness and comprehension of polysemous lexis, thereby improving their understanding of both everyday and genre-specific meanings. The study focussed on how polysemous words, those with both common and academic or scientific meanings (Vygotsky, Reference Vygotsky1978), can be better understood through cognitive approaches. Specifically, Hill showed that employing such approaches within learners’ ZPD increased their awareness of metonymic extensions, facilitating the shift from everyday to disciplinary meanings. In this regard, sociocultural theory proves valuable for understanding the role of language in cognitive development: linguistic development reflects cognitive growth, and meaningful social interaction among teachers, students, and peers supports learners’ progression along the learning continuum.

Although not a cognitive theory per se, Bloom’s Taxonomy is a widely used framework that classifies educational goals into levels of complexity and specificity. Originally developed in the 1950s, it was later revised by Anderson and Krathwohl (Reference 45Anderson and Krathwohl2001), who reorganised the taxonomy into a hierarchy of cognitive skills – ranging from lower-order thinking skills (LOTS), such as remembering, understanding, and applying, to higher-order thinking skills (HOTS), such as analysing, evaluating, and creating. CLIL can promote the development of HOTS by encouraging learners to engage with complex subject matter through the medium of a second or foreign language, thereby deepening both content understanding and language proficiency.

In their study conducted in the region of Murcia, Spain, Campillo Ferrer and Miralles-Martínez (Reference Campillo-Ferrer and Miralles-Martínez2022) investigated the development of LOTS by CLIL teachers in science and social studies during the first two years of primary education. Employing a mixed-methods approach that combined qualitative and quantitative techniques, the researchers examined the extent to which LOTS are fostered within the integrated CLIL framework. Their findings revealed that most of the cognitive practices promoted by CLIL teachers focussed on enhancing students’ comprehension. The authors argue that CLIL can significantly support the development of LOTS, contributing to learners’ cognitive progression, a conclusion that is consistent with previous research in the field (Alonso-Belmonte & Fernández-Agüero, Reference Alonso-Belmonte, Fernández-Agüero, Kırkgöz and Dikilitaş2018).

More broadly, CLIL is regarded as a pedagogical approach capable of fostering both LOTS and HOTS, thereby enhancing overall cognitive development through the simultaneous teaching of foreign language and subject content using diverse techniques and activities (Coyle et al., Reference Coyle, Hood and Marsh2010; Tarabar & Neslanović, Reference Tarabar and Neslanović2021). However, it is important to note that despite the widespread recognition of Bloom’s Taxonomy, recent research highlights that the transition from LOTS to HOTS is often inadequately addressed or misunderstood in classroom practice (Prakash & Litoriya, Reference Prakash and Litoriya2021).

Research suggests that cognitive development lies at the core of CLIL learning (Marsh, Díaz-Pérez, Frigols Martín, Langé, Pavón Vázquez, & Trindade, Reference Marsh, Díaz-Pérez, Frigols Martín, Langé, Pavón Vázquez and Trindade2020) and that CLIL can enhance human cognition by explicitly engaging with concepts and promoting active participation (Hietaranta, Reference Hietaranta2015), sometimes even in comparison to learners taught in their L1. For example, Jäppinen (Reference Jäppinen2005) conducted a study in Finnish CLIL programmes demonstrating statistically significant differences in cognitive development between learners taught through an FL and those taught through their L1. The study involved 669 Finnish mainstream L1 learners aged 7–15 in a public comprehensive school. The experimental group (335 learners) received instruction in English, French, or Swedish, while the control group (334 learners) was taught in Finnish. Results indicated that CLIL instruction had a positive impact on cognitive development. Specifically, Jäppinen found that learners in the CLIL group were guided to construct complex concepts and cognitive schemata, which ultimately enabled them to outperform their peers in the control group.

Against this backdrop of cognitive development, Systemic Functional Linguistics (SFL) (Halliday & Matthiessen, Reference Halliday and Matthiessen2014; Martin & Rose, Reference Martin and Rose2007) has increasingly been applied to CLIL. SFL is a language theory centred around the notion of language function, prioritising the use of language in real-world contexts over purely structural analyses. SFL supports understanding how language operates across different subject areas, thereby facilitating the integration of language and content in CLIL classrooms (Llinares & McCabe, Reference 57Llinares and McCabe2023). Additionally, SFL contributes to CLIL by addressing motivation, task design, pragmatic development, speech functions, and evaluative language in writing (Llinares & Morton, Reference Llinares and Morton2017). It is also effective for identifying lexico-grammatical features in CLIL students’ productions, including defining cognitive discourse functions (Llinares & Nashaat-Sobhy, Reference Llinares and Nashaat-Sobhy2021).

Contributing to this discussion, Evnitskaya and Dalton-Puffer (Reference Evnitskaya and Dalton-Puffer2023) addressed a critical concern in CLIL: the potential mismatch between students’ cognitive level and their L2 proficiency. Using a systemic functional approach, they developed a conceptual map based on an exploratory, data-driven analysis of an oral learner corpus in both L2 English and L1 Spanish, focussing on science and history topics in primary bilingual schools in Madrid. Their analysis revealed conceptual and linguistic difficulties in forming complete and appropriate categorisations in both languages, with subject-specific tendencies in categorising. These findings suggest that challenges in CLIL are not solely attributable to limited L2 proficiency but also arise from the inherent complexity of subject matter itself, highlighting the need for effective scaffolding that supports both thinking and language development.

Further evidence of the interplay between language and cognition in CLIL is provided by Whittaker and McCabe (Reference Whittaker and McCabe2023), who analysed evaluative language in a longitudinal corpus of students’ texts written in L2 English across different disciplines (natural science, history, art). The texts were collected from the same students at the end of primary school (aged 11+) and at both the beginning and end of secondary year 2 (aged 13–14). The results showed how students’ cognitive discourse competence (i.e. learners’ ability to process and produce subject-specific language) improved as they developed appropriate field-evaluation couplings in CLIL writing across these disciplines.

Banegas (Reference Banegas2021) further argued that systemic functional grammar can positively affect both content knowledge and pedagogical content knowledge, that is, not only understanding the subject matter itself but also knowing how to teach it effectively by integrating content and language instruction. It may also have implications for curriculum development, pedagogy, and assessment in multilingual education programmes (Lo & Fung, Reference Lo and Fung2020).

Theoretical frameworks like Cummins’ (Reference Cummins and Hornberger2008) distinction between BICS and CALP has had a significant impact on L2 acquisition and educational practices, particularly within the context of CLIL. BICS, Basic Interpersonal Communication Skills, refers to everyday language used in casual conversations, while CALP, Cognitive Academic Language Proficiency, involves more advanced language skills needed for academic tasks, such as understanding lessons or writing essays. In the CLIL context, both BICS and CALP play important roles: BICS, which is social and communicative language, is acquired more easily but may not be sufficient for academic demands. CALP, on the other hand, requires sustained, targeted instruction. CLIL aims to develop CALP by immersing students in academic content taught through the medium of the FL, thus enhancing their ability to use the language in cognitively demanding contexts.

Based on this distinction, Ranney (Reference Ranney2012) examined the pedagogical implications of the BICS/CALP framework over three decades, drawing on linguistic approaches such as corpus linguistics and SFL. Her findings suggest that while BICS is acquired fairly quickly through interaction, CALP development benefits greatly from explicit instruction and extensive practice in both oral and written modalities.

Wakabayashi’s (Reference Wakabayashi2002) study on high school students attending an international school in Japan adds further support through Cummins’ Common Underlying Proficiency (CUP) model, which posits that cognitive and academic skills developed in one language can transfer across languages, enabling bilingual learners to draw on a shared cognitive foundation. Her research demonstrated that cognitive and academic skills developed in one language can transfer to another, supporting bilingual learners across both languages. The study also found that early academic instruction in Japanese helped students’ CALP development in English. Consistent with this, Lorenzo and Rodríguez (Reference Lorenzo and Rodríguez2014) observed that CALP in CLIL environments tends to evolve gradually, with complex syntax and textual cohesion improving over time.

Taken together, these studies and theoretical perspectives highlight how language learning and content mastery are deeply interconnected, requiring careful attention to both cognitive and linguistic developments. Effective scaffolding, understanding the difference between everyday and academic language, and transferring skills between languages all help learners succeed. This shows the importance of providing focussed support that tackles both the difficulty of the subject and language skills.

2.3 Key Concepts and Principles of CLIL

There is no doubt that any discussion of the principles underpinning CLIL methodology must first and foremost refer to the 4Cs framework (Bower, Cross, & Coyle, Reference Bower, Cross, Coyle and Bower2020; Coyle, Reference Coyle2007; Coyle et al., Reference Coyle, Hood and Marsh2010), due to its outstanding relevance and usefulness over the years.

The 4Cs framework comprises four ‘building blocks’ (Coyle et al., Reference Coyle, Hood and Marsh2010, p. 41), which are essential to understanding CLIL:

• – Content: the subject matter to be taught and learned

• – Communication: the process of language learning and use

• – Cognition: the growth of thinking and learning processes

• – Culture: the development of intercultural awareness and global citizenship

The 4Cs framework was developed by Coyle (Reference Coyle2007), who conceptualised content, communication, cognition, and culture as key components of CLIL. Mehisto, Frigols, and Marsh (Reference Mehisto, Frigols and Marsh2008) proposed a similar model, replacing culture with community, which they defined as the learner’s participation in both local and global contexts. Other researchers have further adapted this model. For example, Hemmi and Banegas (Reference Hemmi, Banegas, Hemmi and Banegas2021) incorporated both community and culture, highlighting the interrelationship between these two dimensions. Signalling the vitality of the framework, Sakamoto (Reference 64Sakamoto2022) retained the original 4Cs but proposed a fifth C, criticality (i.e. the capacity for critical thinking and reflection), to enhance the robustness of the approach, particularly in the Japanese educational context.

Together with the 4Cs framework, Coyle et al. (Reference Coyle, Hood and Marsh2010) outlined seven pedagogical principles. They are personalised learning, linking content–cognition–language, recognising cognitive language demands, providing transparent and contextualised language, emphasising interaction, promoting intercultural awareness, and ensuring context-sensitive implementation. These principles promote the dual aim of learning to use language effectively and using language to learn meaningfully. As Bower et al. (Reference Bower, Cross, Coyle and Bower2020, p. 8) assert ‘without being prescriptive, these seven principles provide guidance for teachers on the kinds of teaching and learning experiences best suited to CLIL contexts, when working with the 4Cs in practice as a framework for bringing language and content together’.

More recently, these authors (see, for example, Coyle & Meyer Reference Coyle and Meyer2021; Coyle, Meyer & Staschen-Dielmann, Reference Coyle, Meyer and Staschen-Dielmann2023; and Meyer & Coyle, Reference Meyer and Coyle2017) have developed their work into what is now known as Pluriliteracies Teaching for Deeper Learning approach. While the 4Cs framework emphasises the integration of content, cognition, culture, and communication, the pluriliteracies approach focusses on learners’ progression in subject-specific literacies across languages. This involves using appropriate academic genres and styles to express content knowledge, thereby fostering deeper conceptual understanding. Their approach focusses on guiding learners along structured pathways of knowledge to enhance deeper learning within subject disciplines, reaffirming the idea that the objective is ‘to offer opportunities for deeper learning through a focus on subject-specific literacies’ (Coyle et al., Reference Coyle, Meyer and Staschen-Dielmann2023, p. 12). Although this new model adopts a more holistic and multimodal approach, the 4Cs framework remains highly relevant to CLIL research and practice.

Closely linked to the communication dimension of the 4Cs is another key model: the Language Triptych (Banegas & Mearns, Reference 46Banegas and Mearns2023; Banegas, Montgomery, & Raud, Reference Banegas, Montgomery and Raud2024; Bower et al., Reference Bower, Cross, Coyle and Bower2020; Coyle et al., Reference Coyle, Hood and Marsh2010). This model separates the language dimension into three interrelated constructs:

• – Language of learning: the subject-specific language needed to access concepts and skills related to a given topic.

• – Language for learning: the language required for classroom interaction, collaboration, and learning management.

• – Language through learning: the language that emerges as learners process content, reflect on meaning, and engage in deeper cognitive activity.

For example, in a CLIL science lesson on plant biology, students may use language for learning to ask the teacher clarifying questions or to work in pairs. They will need the language of learning to understand and use subject-specific terms such as stomata, carbon dioxide, and glucose. Through group discussions or writings, students use and expand language through learning by connecting new content to prior knowledge, explaining processes in their own words, or drawing comparisons with other systems (e.g. human respiration). This triptych helps both learners and teachers to better understand and manage the linguistic demands of CLIL instruction. It also supports effective lesson planning and scaffolding, enabling learners to engage more fully with both language and content (Hemmi & Banegas, Reference Hemmi, Banegas, Hemmi and Banegas2021).

2.4 Summary

CLIL has emerged as a timely and significant contribution to the promotion of L2 learning and teaching. Although the term was coined in Europe in the 1990s, the approach is shaped by diverse historical, political, and social factors, drawing inspiration from North American immersion programmes, with which it shares several commonalities. Indeed, CLIL can be viewed along a continuum from content-led to language-led instruction, depending on contextual and institutional priorities.

In this section, we have outlined the theoretical underpinnings and core concepts of the CLIL approach, supported by relevant research and educational models. These include cognitive and sociocultural perspectives, as well as systemic functional linguistics and pluriliteracies frameworks. At its foundation, CLIL is guided by the principle of integration (Ruiz de Zarobe & Cenoz, Reference Ruiz de Zarobe and Cenoz2015), placing language, content, thinking, and communication at the centre of learning. This integrated approach supports deeper understanding, encourages higher-order thinking, and enhances academic language proficiency, while also contributing to learners’ overall development.

3.1 Origins of CLIL

Education in an L2 or FL has had a strong precedence in different parts of the world, such as in European educational institutions, which have a long tradition of teaching content through an additional language. What is probably new today is that these programmes now reach a much broader spectrum of learners (Tedick, Reference Tedick, Bower, Coyle, Cross and Chambers2020). CLIL has its roots in European multilingual policies, but there is no doubt that it was also influenced by earlier North American immersion and bilingual education programmes (Gabillon, Reference Gabillon2020; Pérez Cañado, Reference Pérez Cañado2012). Much evidence from Canada and the United States (e.g. Cummins, Reference Cummins1989; Genesee, Reference Genesee1987, Reference Genesee1994, Reference Genesee, Bhatia and Ritchie2004; Genesee & Jared, Reference Genesee and Jared2008; Lyster, Reference Lyster1987; and Wesche, Reference Wesche, Burmeister, Piske and Rohde2002) demonstrated the success of such programmes in terms of linguistic, content, and motivational outcomes.

In Europe, CLIL emerged in connection with the growing emphasis on multilingualism, linguistic and cultural diversity, and globalisation. This explains why early developments in CLIL are often associated with the European Union’s (EU) support for a multilingual Europe. This connection is clearly reflected in the EU’s educational policies, which highlight the importance of teaching multiple subjects in non-native languages. As stated in a resolution by the European Parliament:

In fact, the ‘mother tongue + 2’ objective was already present in the EU Commission’s 1995 White Paper on Education and Training, with its proposal that EU citizens should master three European languages: their L1, a language of international communication, and a personal adoptive language. Since then,language policies, implemented at different levels of commitment, have been based on institutional documents and recommendations for language learning, which address CLIL as an appropriate solution to achieve that objective (Nieto Moreno de Diezmas & Custodio Espinar, Reference Nieto Moreno de Diezmas and Custodio Espinar2022; Ruiz de Zarobe, Reference Ruiz de Zarobe, Banegas and Zappa-Hollman2023).

Thus, CLIL as an educational approach was quickly adopted as a key instrument in education, supported by European institutions and language policy makers, and promoted by the European Commission as a method for improving language learning and the quality of teaching.

Furthermore, it was recommended as a preferred educational approach because of its multiple benefits, which included the development of intercultural communication skills, improved language proficiency and oral communication skills, opportunities to study content through different insights, and increased motivation and confidence of the learners. In addition, ‘linguistic and cultural competences lie at the heart of education. Proficiency in the first language may facilitate the learning of other languages, while early language learning, bilingual education and Content and Language Integrated Learning (CLIL) are effective means of improving language learning provision’ (Council of Europe, 2008, para. 21).

Following the European Commission’s recommendations to achieve multilingualism, most EU member states implemented CLIL in compulsory education, although responses to the approach varied from one member state to another. A number of parameters accounted for these differences, such as the population segments, age groups, types and language level of teachers involved, monolingual versus bilingual settings, and the role of assessment (Pérez Cañado, Reference Pérez Cañado2016a). Despite these differences, and considering this diversity, early developments of the CLIL approach were heavily policy driven. What is particularly interesting is that, alongside institutional interests, CLIL also gained momentum through a variety of individual projects led by school communities and stakeholders, all aimed at improving L2 learning. This two-fold trajectory, one driven by policy and the other by grassroots initiatives, helps explain the holistic nature of CLIL, contributing to its broader impact in international contexts.

3.2 CLIL around the Globe

Over the years, CLIL has gained ground beyond Europe, expanding to various countries around the world, including those in Latin America and Asia, where it adapts to local sociopolitical, historical, and cultural contexts as well as specific educational environments.

In South America, CLIL has been implemented mainly in private education sectors, in primary, secondary, and higher education settings (Banegas, Poole & Corrales, Reference Banegas, Poole and Corrales2020). Research in the region has shown mixed results regarding the effectiveness of CLIL in supporting language learning and cognitive development (Banegas, Reference Banegas2021). However, research also shows promise in improving communicative competence, motivation, and even intercultural communication (Ruiz de Zarobe & Banegas, Reference Banegas, Montgomery and Raud2024). Although CLIL has been rapidly adopted in South American countries, and stakeholders show significant enthusiasm for its implementation, the approach requires specialised teacher training and the development of teacher-made CLIL materials. Additionally, more structured pre-service teacher training programmes are needed to prepare educators for CLIL (Banegas, Reference Banegas2021; Banegas & del Pozo Beamud, Reference Banegas and del Pozo Beamud2020).

In this regard, de Mejía and Garzón-Díaz (Reference de Mejía, Garzón-Díaz, Ruiz de Zarobe and Banegas2024) highlight several key issues for CLIL implementation in South America. These include the need for a situated CLIL approach, ‘adapting rather than adopting CLIL methodologies developed in other countries, particularly in Europe’ (de Mejía & Garzón-Díaz, Reference de Mejía, Garzón-Díaz, Ruiz de Zarobe and Banegas2024, p. 19). Although the prospects for CLIL in countries such as Colombia appear very positive (Cuesta Medina & Ruiz de Zarobe, Reference Cuesta Medina, Ruiz de Zarobe, Ruiz de Zarobe and Banegas2024; Garzón-Díaz, Reference Garzón-Díaz2018), researchers in countries such as Brazil (Landau, Albuquerque Paraná, & Siqueira, Reference 55Landau, Albuquerque Paraná, Siqueira, Hemmi and Banegas2021; Megale & Liberali, Reference Megale, Liberali, Ruiz de Zarobe and Banegas2024) present a more critical view of the approach, advocating for language education that challenges monoglossic and monocultural perspectives and avoids perpetuating colonialism in the region. A situated CLIL approach also promotes situated language teacher education (Banegas & Ruiz de Zarobe, Reference Banegas, Ruiz de Zarobe, Ruiz de Zarobe and Banegas2024), building stronger links between teacher education and school policy within a decolonising curriculum.

A second key issue raised by de Mejía and Garzón-Díaz (Reference de Mejía, Garzón-Díaz, Ruiz de Zarobe and Banegas2024) concerns the (inter)cultural dimension of the approach. As Banegas and Sánchez (Reference Banegas and Sánchez2023) argue, culture in CLIL can be enriched by adopting a social justice approach to prevent issues such as discrimination (Banegas and Ruiz de Zarobe, Reference Banegas, Ruiz de Zarobe, Ruiz de Zarobe and Banegas2024; Porto, Reference Porto, Banegas and Zappa-Hollman2023). In practice, this could be addressed through projects involving all stakeholders in the school community.

In Asian school settings, research has shown significant potential for CLIL in improving both language proficiency and content knowledge. For example, Yamazaki (Reference Yamazaki, Tsuchiya and Pérez Murillo2019) demonstrated how CLIL, combined with collaborative learning, can enhance students’ competence in using content knowledge in everyday life in Japan, even among students of different proficiency levels. Similarly, the CLIL approach showed potential to improve content, communication, cognition, and community/culture awareness compared to regular EFL lessons in Japanese primary schools (Yamano, Reference Yamano, Tsuchiya and Pérez Murillo2019).

Moreover, studies from other Asian countries provide further insights. In China, Zhu, Liu, Shu, and Wang (Reference Zhu, Liu, Shu and Wang2024) compared two primary schools, one implementing a CLIL science programme and the other offering a conventional science programme. The results indicated no statistically significant differences in science achievement between CLIL and non-CLIL students, though the former achieved higher mean scores. Interestingly, receptive language skills correlated significantly with science scores, whereas productive language skills did not. Additionally, Beaudin (Reference Beaudin2021) showed that CLIL implementation improved students’ English proficiency and enjoyment in elementary schools in southern Taiwan. Students generally enjoyed CLIL and believed it enhanced their English skills. Similarly, Rafi and Morgan (Reference Rafi and Morgan2023) found that a blended approach (i.e. integration of face-to-face and online learning) kept students engaged, improved knowledge acquisition, and created a dynamic learning space in a Bangladeshi school.

However, despite generally positive learner responses, challenges remain, particularly in balancing content and language learning and addressing the needs of learners with limited English proficiency (Yamazaki, Reference Yamazaki, Tsuchiya and Pérez Murillo2019). For example, Karabassova (Reference Karabassova2018) showed how CLIL implementation in the trilingual context of Kazakhstan led teachers to prioritise content over language, focussing on teaching through another language but with limited pedagogical awareness. Mehisto, Winter, Kambatyrova, and Kurakbayev (Reference Mehisto, Winter, Kambatyrova and Kurakbayev2023) also revealed in a large-scale programme in Kazakhstan, the drawbacks of a centralised policy initiative, including a one-size-fits-all approach to teacher development and a mismatch between programme intentions and implementation.

Research conducted across diverse geographical contexts demonstrates that the European CLIL model cannot be directly transferred to other regions due to differing educational traditions, linguistic landscapes, and policy environments. In countries such as Japan, CLIL has emerged as a response to the need to reform traditional grammar-focussed English as a Foreign Language (EFL) instruction, promoting more communicative and contextually meaningful pedagogies. In Mainland China, the adoption of CLIL has been largely driven by efforts to internationalise education and enhance English proficiency in preparation for global competitiveness. In parts of South America, CLIL has been integrated into broader educational reforms aimed at modernising curricula, improving foreign language outcomes, and fostering stronger links with international academic and economic spheres. These varied motivations illustrate CLIL’s adaptability to region-specific educational goals and challenges.

In line with this, Banegas (Reference Banegas2021) suggests that CLIL implementation should be grounded in context-responsive models that reflect local needs. Similarly, Tsuchiya (Reference Tsuchiya, Tsuchiya and Pérez Murillo2019) argues that CLIL has the potential to revolutionise language education in Japan by prioritising the development of generic competences over traditional language acquisition goals. In Japan, CLIL is often framed as ‘soft CLIL’ within EFL contexts (Ikeda, Izumi, Watanabe, Pinner, & Davis, Reference Ikeda, Izumi, Watanabe, Pinner and Davis2023), while in Hong Kong, it is more commonly referred to as English-medium instruction (EMI) (Cheng, Reference 49Cheng2020; Wannagat, Reference Wannagat2007). In each setting, the complex interplay of linguistic diversity and educational priorities gives rise to distinct challenges and opportunities for CLIL implementation.

Across these contexts, as has also frequently been noted in Europe, there remains a pressing need for more teacher-designed CLIL materials (for example, Penny & Ruiz de Zarobe, Reference Penny, Ruiz de Zarobe, Cirocki, Farrelly and Sapp2024; Ting, Reference Ting, Huettner and Dalton-Puffer2024) and professional development to support educators in delivering CLIL programmes effectively. This global picture points to a broader requirement for ongoing research and locally adapted approaches, which, as in Europe, call for a reconceptualisation of language learning and the adoption of innovative pedagogical perspectives (San Isidro, Reference San Isidro2018).

CLIL has evolved from a European initiative into a global educational approach, adapting to different contexts and needs. While it holds considerable promise for integrating content and language learning, significant challenges remain due to the varying conditions of language education across regions (Mehisto et al., Reference Mehisto, Winter, Kambatyrova and Kurakbayev2023; Siqueira, Landau & Albuquerque Paraná, Reference Siqueira, Landau and Albuquerque Paraná2018). In many of these settings, CLIL initiatives often rely on the local efforts of teachers and educational personnel. However, ensuring its long-term sustainability requires broader political support and greater coordination among key stakeholders.

3.3 Summary

CLIL has been widely adopted in Europe since the mid-1990s as part of a European multilingual policy aimed at enabling citizens to use several languages functionally. It has gained prominence in Europe and has also spread globally to regions such as Asia and Latin America, with each adapting the approach to its unique context and educational needs. Continued research and context-specific adaptation are essential for the effective implementation and ongoing development of CLIL worldwide.

4.1 The Effects of CLIL on Language Learning

Research into the effectiveness of CLIL for language learning has been a central focus over recent decades. Much of this interest has revolved around whether CLIL can foster effective language acquisition or serve as an innovative approach to enhancing language performance (Pérez Cañado, Reference Pérez Cañado2016b). Since much of this research has been conducted by applied linguists, early studies predominantly concentrated on language learning outcomes.

Early studies (see, for example, Dalton-Puffer, Reference Dalton-Puffer2011 and Ruiz de Zarobe, Reference 63Ruiz de Zarobe, Ruiz de Zarobe, Sierra and Gallardo del Puerto2011, for overviews) highlighted both the benefits of the approach and its problematic areas. On the basis of this earlier work, Ruiz de Zarobe (Reference Ruiz de Zarobe, Juan-Garau and Salazar-Noguera2015) expanded the research by identifying the competences, areas, or sub-skills where clear gains were observed:

• Listening

• Reading

• Receptive vocabulary

• Speaking (fluency, risk-taking associated with low affective filter)

• Writing (fluency and lexical and syntactic complexity)

• Some morphological phenomena

• Emotive/affective outcomes

and those areas which seemed unaffected or yielded indefinite results:

• Syntax

• Productive vocabulary

• Informal/non-technical language

• Writing (accuracy, discourse skills)

• Pronunciation (degree of foreign accent)

It should be noted that many of these studies compared CLIL learners with non-CLIL learners in mainstream classes (i.e. EFL learners). In some cases, CLIL learners received a number of CLIL lessons (e.g. science) in addition to traditional EFL instruction. As a result, the total number of hours of English exposure differed between the two groups. This led to calls for comparisons between CLIL learners and non-CLIL learners with an equivalent number of English hours, even if the latter were from higher year groups (see, for instance, Lasagabaster, Reference Lasagabaster2008 and Ruiz de Zarobe, Reference Ruiz de Zarobe, Dalton Puffer, Nikula and Smit2010).

As pointed out by Ruiz de Zarobe (Reference Ruiz de Zarobe, Juan-Garau and Salazar-Noguera2015), some of the outcomes were inconclusive due to the limited research available at the time on certain skills or competences, such as listening. In addition, the small sample sizes in some studies, along with the scarcity of longitudinal research and the need for more robust statistical analyses, were noted as limitations (Pérez Cañado, Reference Pérez Cañado2012).

More up-to-date research has tried to overcome some of these limitations. Notably, Pérez Cañado (Reference Pérez Cañado2018a) reported on a longitudinal study carried out with 1,033 CLIL students and 991 EFL learners in 53 public, private, and charter schools across 12 Spanish provinces into the effects of CLIL on FL achievement (grammar, vocabulary, reading, listening, and speaking) from primary education to compulsory secondary education and baccalaureate. Controlling for the homogeneity of both strands (bilingual/CLIL and non-bilingual/EFL), intergroup and intragroup evolution was examined. Results revealed that the CLIL group showed significant differences in overall proficiency already in primary education, with a positive and more marked difference in secondary education. Discriminant analyses demonstrated that the CLIL approach explained these differences better than other factors such as verbal intelligence, extramural exposure to English, or socioeconomic status (SES).

These positive results have been supported by other studies. For example, Merino and Lasagabaster (Reference Merino and Lasagabaster2018) showed how CLIL learners obtained significantly higher scores in English as a third language (L3) compared to non-CLIL groups in a one-year longitudinal study of secondary school students, although similar development was observed in both rounds of testing between CLIL and non-CLIL groups. No significant differences were found in the students’ L1 and L2 (Spanish and Basque) developments, despite the fact that CLIL students were less exposed to Basque in the school context. In a rural context in Galicia, another region in northern Spain, San Isidro and Lasagabaster (Reference San Isidro and Lasagabaster2019) revealed how CLIL students showed greater improvement than their non-CLIL counterparts over the two years of the project, both in general proficiency and in the four language skills (listening, speaking, reading, and writing), in secondary education. Interestingly, the CLIL group’s improvement in Galician and Spanish was higher than that of the non-CLIL group, and there seemed to be no negative effect resulting from minimising the exposure to Galician in the CLIL group.

Comparing CLIL and non-CLIL groups in public schools, Martínez Agudo (Reference Martínez Agudo2020) found that CLIL students in public schools had significant advantages in English language proficiency at the end of secondary education, which was even more marked at the end of the first year of baccalaureate. On the other hand, non-CLIL learners in public schools showed significantly lower performance on all measures at all levels compared with non-CLIL learners in charter schools. However, when comparing public school CLIL students with charter school non-CLIL students, no statistically significant differences were found in the language skills assessed, which seemed to indicate that CLIL compensated for the advantage that charter schools tend to have in overall academic performance and English language proficiency.

Some of these studies, despite addressing limitations identified in earlier research, produced results that remained largely consistent with previous findings. As Nieto Moreno de Diezmas and Custodio Espinar (Reference Nieto Moreno de Diezmas and Custodio Espinar2022, p. 62) observe, ‘interestingly enough, most of the findings of these longitudinal studies using meticulous statistical analyses backed up results and trends already found in previous cross-sectional investigations’.

Apart from recent studies on language outcomes, another wave of research has undertaken several meta-analyses to investigate the effects of CLIL. These include Goris, Denessen, and Verhoeven (Reference Goris, Denessen and Verhoeven2019), who conducted a review of longitudinal studies on the effects of CLIL on various language skills in EFL. The findings provided clear indications of the contexts in which CLIL led to significantly better outcomes in L2. CLIL was best profiled in contexts such as Spain, with strong support for the introduction of CLIL, although the country remained a ‘low EFL proficiency country’ in the EU and, according to the authors, is still at less advanced stages of EFL skills. Countries such as the Netherlands and Germany, with a high level of EFL proficiency and an elitist and highly selective CLIL, have gained little on the assessment scales.

Lee, Lee, and Lo (Reference Lee, Lee and Lo2023) extended the earlier meta-analysis by Lo and Lo (Reference Lo and Lo2014) regarding the effectiveness of English-medium instruction on secondary-level students’ English learning in Hong Kong, incorporating 44 samples from 38 primary studies. Their findings revealed the effectiveness of CLIL for improving English language competence compared to mainstream education. However, greater benefits were observed for learners whose first language was linguistically closer to English and in studies measuring vocabulary acquisition. In contrast, lower effectiveness was reported in studies assessing productive skills rather than receptive or overall proficiency. Building on this work, Lee, Lee, and Lo (Reference Lee, Lee and Lo2025) conducted a multi-level meta-analysis focussed specifically on primary education. The results indicated that CLIL significantly enhances foreign language learning, particularly speaking skills, without adversely affecting content knowledge. Nevertheless, the effectiveness varied depending on the research design, and a slight decline in impact over time highlighted the need for more robust and context-responsive research approaches.

In brief, these studies suggest that CLIL is often effective in improving FL skills, particularly in English. However, the effectiveness of CLIL may be influenced by factors such as the skill analysed or the linguistic relationship between the learners’ L1 and the target language. Since CLIL addresses the balance between content and language instruction, the following section will discuss the outcomes in terms of content of the approach, as well as the effect on the L1.

4.2 The Effects of CLIL on Content and L1 Learning

The effectiveness of CLIL in the school environment shows a complex picture. Although, as seen in the previous section, many CLIL programmes systematically improve L2 acquisition, their impact on content learning and their effect on the L1 varies. While the earlier discussion focussed specifically on L2 outcomes, the central aim of CLIL and the most commonly assessed domain, this section considers content and L1 learning together, as both reflect core aspects of students’ academic development in their familiar languages. Examining them jointly provides a fuller understanding of whether CLIL supports or compromises students’ broader educational progress beyond the target language.

Positive outcomes have been found in different geographical contexts, mainly in European settings. Some of the earliest studies on content performance include countries such as Finland, where Jäppinen (Reference Jäppinen2005) found that CLIL environments provided favourable conditions for content learning, with no statistically significant differences between students learning mathematics and science in their mother tongue and those learning through English in secondary education. Similarly, Admiraal, Westhoff, and de Bot (Reference Admiraal, Westhoff and de Bot2006) in the Netherlands found no differences in subject outcomes in their longitudinal study of school-leaving examinations, despite some content subjects (history and geography) having been taught through English. In Switzerland, Stohler (Reference 65Stohler2006) examined several schools where German or French were used as a foreign language and found no significant differences in knowledge acquisition when students were taught in their L1 or through the FL.

Moving forward in time, Surmont, Struys, Noort, and Craen (Reference Surmont, Struys, Van Den Noort and Van De Craen2016) examined first-year secondary school pupils in a school in Flanders, the Dutch-speaking part of Belgium. The results showed how CLIL seemed to positively impact pupils’ mathematical performance, even after a short period (3 months). A few years later, in their longitudinal study, Bulté, Surmont, and Martens (Reference 48Bulté, Surmont and Martens2021) investigated the effect of learning content subjects in French on secondary school students’ listening comprehension and speaking in French, as well as their reading comprehension in Dutch. The results showed that following a CLIL programme positively affected listening comprehension and speaking in French, while it did not impact reading comprehension in Dutch, their L1. These results suggest that even a limited amount of CLIL (one to five hours per week) may positively influence learners’ proficiency in the target language without detrimental effects on the L1.

In Spain, as mentioned in the previous section, Merino and Lasagabaster (Reference Merino and Lasagabaster2018) and San Isidro and Lasagabaster (Reference San Isidro and Lasagabaster2019) showed how CLIL students outperformed their non-CLIL counterparts in two bilingual communities in Spain (Basque Country and Galicia), without negatively affecting the official languages of the community, despite a reduction in time allocated to those languages. These findings corroborated earlier research in the Basque Country (e.g. Grisaleña, Alonso, & Campo, Reference 53Grisaleña, Alonso and Campo2009).

Also in Spain, particularly in Andalusia, Pérez Cañado (Reference Pérez Cañado2018a), in the large longitudinal study discussed earlier, showed that CLIL had a beneficial impact on content learning, with a significant positive effect over time (from primary to secondary education), without negatively affecting L1 proficiency. These results were further supported by Hughes and Madrid (Reference Hughes and Madrid2019), whose findings indicated that CLIL instruction had no detrimental effects, and even positive ones, on secondary students’ science learning. Similarly, Navarro-Pablo and López Gándara (Reference Navarro-Pablo and López Gándara2020) found that students in CLIL programmes performed better in end-of-year Spanish language and literature assessments than their non-CLIL peers, regardless of whether they were in rural or urban settings. The amount, distribution, and type of L1 and FL input in CLIL classes could explain these positive results in the L1.

In addition, Barrios (Reference Barrios and Pérez Cañado2021), also working within the same Andalusian project, showed that curricular competence in Spanish as L1 was not negatively affected, as L1 school grades of CLIL students were comparable to those of students in regular classes. However, intervening variables such as setting, gender, parents’ education level, and extramural exposure to English seemed to have different effects on the grades of CLIL and non-CLIL groups.

More recently, in French-speaking Belgium, Szmalec et al. (Reference Szmalec, Simonis, Hauspie, Ordonez Magro, Hiligsmann, Van Mensel and Galand2024) examined official end-of-year external evaluations of a large number of primary and secondary school students in both CLIL and non-CLIL programmes. For primary students, external assessments focussed on mathematics, history and geography, science, and French, while for secondary students, they assessed history and French. The results showed that CLIL students, like their non-CLIL peers, achieved the curriculum goals and acquired the necessary subject matter, even when taught through an FL (English or Dutch). These findings held even when controlling for cognitive and demographic variables. Notably, these evaluations are identical for all schools in French-speaking Belgium and are conducted in the main school language, French, which makes the results especially significant.

However, some research has shown negative or limiting effects of CLIL on content learning. In Germany, Dallinger, Jonkmann, Holm, and Fiege (Reference Dallinger, Jonkmann, Hollm and Fiege2016) compared CLIL and non-CLIL learners of English, controlling for a range of learner, classroom, and teacher characteristics. While the CLIL group showed greater improvement in listening comprehension, this was not the case for general English skills. Moreover, in history, both groups achieved comparable knowledge gains over the school year, even though CLIL students received more hours of instruction (three hours per week versus two). These outcomes suggest that CLIL programmes may need additional instructional time to achieve equivalent content learning outcomes.

Three studies in Spain also reported disappointing results. In the Community of Madrid, Sotoca (Reference Sotoca2014) analysed students in third to sixth grade across twelve public schools. Academic performance was measured via grade point average (GPA) and external examinations. External tests showed significant differences in favour of bilingual schools in language and mathematics in year 6, but not in year 4. However, school grades revealed significant differences in favour of non-bilingual schools in environmental knowledge and English. Also in Madrid, Anghel, Cabrales, and Carro (Reference Anghel, Cabrales and Carro2016) evaluated a bilingual programme in which at least science, history, and geography were taught in English. Their findings showed a clear negative effect on test scores in subjects taught in English, especially among children whose parents had not completed upper secondary education. This negative effect was not present for students taught in Spanish.

Similarly, Fernández-Sanjurjo, Arias Blanco, and Fernández-Costales (Reference Fernández Sanjurjo, Blanco and Fernández-Costales2017), also in Spain, confirmed similar results, finding that students taught in Spanish performed slightly better in science at the end of primary education than those taught in English. These findings align with earlier studies (Bergroth, Reference Bergroth, Björklund, Mard-Miettinen, Bergström and Södergård2006; Seikkula-Leino, Reference Seikkula-Leino2007), which suggest that non-CLIL programmes produce a higher number of overachieving students. Fernández-Sanjurjo et al. also point to socioeconomic factors: students from lower SES backgrounds tend to obtain lower scores in CLIL programmes.

As this sample of studies shows, the effects of CLIL on content and L1 learning are less conclusive than those on L2 acquisition. Overall, research suggests that CLIL programmes do not hinder L1 development and may even support it. Similarly, some studies report positive outcomes in content learning, though the degree of benefit appears to depend on contextual factors such as programme intensity and implementation. As Morton notes, ‘content has been something of a poor relation in CLIL research and practice’ (Morton, Reference Morton, Banegas and Zappa-Hollman2023, p. 523), with relatively few studies addressing this domain. While some findings suggest that CLIL learners outperform their non-CLIL peers in content subjects, others point to neutral or even negative effects. Ultimately, other variables likely influence the success of CLIL implementation. In the following section, we focus on motivation and attitudes towards CLIL.

4.3 Attitudes and Motivation in CLIL

Motivation is widely regarded as one of the most influential factors in L2 acquisition. As in other L2 learning contexts, learner attitudes and motivation have been the focus of extensive research in CLIL settings. This field has evolved considerably over time: early studies often relied on small-scale or cross-sectional data, but recent years have seen an increase in longitudinal research, the use of more representative samples, and more sophisticated statistical analyses. This shift reflects a growing effort to better understand the dynamic and multifaceted nature of motivation in CLIL contexts and to produce more reliable findings.

Research consistently shows that students and families involved in CLIL develop more positive attitudes and higher motivation towards language learning compared to non-CLIL settings (Amengual-Pizarro & Prieto-Arra, Reference Amengual-Pizarro, Prieto-Arra, Juan-Garau and Salazar-Noguera2015; Merisuo-Storm, Reference Merisuo-Storm2007; Pérez Cañado, Reference Pérez Cañado2021; Sylvén & Thompson, Reference Sylvén and Thompson2015). Motivational variables also positively affect language achievement (Navarro-Pablo, Reference Navarro-Pablo2018; Pfenninger, Reference Pfenninger2016) and are closely related to strategy use (Gutiérrez & Ruiz de Zarobe, Reference Gutiérrez, Ruiz de Zarobe, Jiménez-Munoz and Lahuerta Martínez2019; Ruiz de Zarobe & Smala, Reference Ruiz de Zarobe and Smala2020) in CLIL contexts. Although most studies focus on English as an FL, positive outcomes have also been found with other languages, such as French. Bower (Reference Bower2019), for instance, revealed favourable perceptions of CLIL methodology and high levels of concentration, effort, enjoyment, and progress, particularly in the Partial Immersion Model, where the depth of cooperation and enhanced linguistic competence promoted greater engagement and motivation.

Several longitudinal studies have sought to analyse the effect of CLIL on motivation. For example, Lasagabaster and Doiz (Reference Lasagabaster and Doiz2017) compared CLIL and non-CLIL learners in secondary schools in the Basque Country. They found that CLIL students were initially more intrinsically and instrumentally motivated and showed a greater interest in foreign languages and cultures. However, their motivation declined over time, likely because the programme lost its novelty.

In another two-year longitudinal study in Spain, Pladevall-Ballester (Reference Pladevall-Ballester2019) examined fifth and sixth graders’ motivation in CLIL and non-CLIL contexts with low FL exposure. She found that CLIL learners increased their motivation over time, even in low-exposure settings, maintaining positive language attitudes. While the subject type had some influence, arts and crafts learners showed a greater increase than science learners, these differences were not statistically significant. The study suggests that CLIL can enhance primary learners’ motivation towards the FL even in contexts with limited exposure.

The intensity of CLIL instruction has also been explored. Somers and Llinares (Reference Somers and Llinares2018) compared first-year secondary students in two strands of CLIL in the Community of Madrid: a high-intensity ‘Sección Bilingüe’ and a low-intensity ‘Programa Bilingüe’. Although students were generally highly motivated, an instrumental orientation predominated, reflecting awareness of the practical value of bilingual education. Students in the low-intensity strand showed lower levels of both intrinsic and instrumental motivation.

Also in the Community of Madrid, Fernández-Agüero and Hidalgo-McCabe (Reference Fernández-Agüero and Hidalgo-McCabe2020) looked into the affective factors influencing students’ experiences in CLIL at the beginning of bilingual secondary education in both high-intensity and low-intensity strands. Findings indicated that instrumental motivation played an important role in these students’ views, with variations depending on the strand, that is, students in the high-intensity strand seemed to see themselves more at ease and in control of their choices, whereas low-intensity strand students experienced more ambivalence over the transition. It needs to be remembered here that students from bilingual schools in the Community of Madrid may have significant differences in their views on education, teachers, and schooling, which may be influenced by their motivation and school characteristics (Buckingham, Álvarez, & Halbach, Reference Buckingham, Fernández Álvarez and Halbach2022; Chaieberras & Rascón-Moreno, Reference Chaieberras and Rascón-Moreno2018).

In their endeavour to analyse the effect of intensity in CLIL, Azpilicueta-Martínez and Lázaro-Ibarrola (Reference Azpilicueta-Martínez and Lázaro-Ibarrola2023) explored the effect of different levels of CLIL exposure on L2 motivation with primary school children. Their results showed that high-CLIL exposure led to significantly higher motivation levels compared to low-CLIL and non-CLIL exposure in all five measures analysed: L2 learning experience, integrativeness, instrumentality-promotion, degree of difficulty of learning languages (including English), and L2 self-appraisal.

Addressing different target languages and instruction levels, de Smet, Mettewie, Hiligsmann, Galand, and Mensel (Reference de Smet, Mettewie, Hiligsmann, Galand and Van Mensel2019) investigated language attitudes and motivation in CLIL on a large scale across two target languages (English and Dutch) and two instruction levels (primary and secondary). Questionnaire data were collected in French-speaking Belgium, measuring the students’ language attitudes in terms of perceived easiness and attractiveness of the target language, and their motivation in terms of expectancy for success, task value, and cost. The outcomes showed that pupils reported more positive attitudes and higher motivation in CLIL compared to non-CLIL and in English compared to Dutch, especially at secondary level. The target language (English vs. Dutch) seemed to play a more crucial role than CLIL vs. non-CLIL regarding language attitudes and motivation.

Differences related to the role of the target language were also identified by Lázaro-Ibarrola and Azpilicueta-Martínez (Reference Lázaro-Ibarrola and Azpilicueta-Martínez2024), who compared motivation in CLIL and non-CLIL primary school learners within a Basque-immersion context. Using Dörnyei’s (Reference Dörnyei, Dornyei and Ushioda2009) L2 Motivational Self System (L2MSS) framework, they reported a significantly positive impact of CLIL on motivation towards English in the ‘ideal L2 self ’, that is, the learner’s imagined future self as a competent L2 user, and in the ‘L2 learning experience’ dimensions. However, they also found a negative impact of CLIL on participants’ instrumental motivation to learn Basque. These findings suggest that increasing exposure to the FL through CLIL lessons may enhance motivation towards English, while potentially diminishing instrumental motivation towards the minority language, Basque.

Based in the Netherlands, the study by Mearns, de Graaff, and Coyle (Reference 59Mearns, de Graaff and Coyle2020) examined motivational differences between learners in Dutch-English bilingual and mainstream education during the first three years of general secondary education. The results showed that learners in the bilingual education programme demonstrated greater motivation in nearly all areas examined, although there was a decline in positivity between the first and third years within the bilingual strand regarding their experience of English lessons. As the authors argue, the key issue is whether there is ‘motivation for or from bilingual education’, that is, whether the learners’ choice to enrol in the bilingual programme influenced the results, as they may have been more inherently motivated from the outset. These findings align with previous research in which students exhibited high motivation before entering such programmes, a phenomenon referred to as the ‘creaming effect’ of selection procedures (San Isidro & Pérez Cañado, Reference San Isidro, Pérez Cañado, Banegas and Zappa-Hollman2023, p. 273; Surmont et al., Reference Surmont, Struys, Van Den Noort and Van De Craen2016, p. 324). Other factors, such as past experience, personality, and personal interests, may also help increase motivation and improve attitudes (Sylvén & Thompson, Reference Sylvén and Thompson2015).

Bringing a different perspective, Rumlich (Reference Rumlich2017), in a large-scale study of CLIL streams in German secondary schools, where up to three content subjects were taught in English, found that after two years, CLIL showed no benefits for overall EFL proficiency or interest in EFL classes, though there was a small increase in EFL self-concept. These results suggest that not all language competences and affective-motivational dispositions benefit equally from CLIL in the German context.

Overall, research indicates that CLIL instruction generally fosters higher motivation and more positive attitudes towards language learning compared to traditional non-CLIL settings. These benefits are observed across various educational levels and subjects, although the stability of motivation may change over time. CLIL may also enhance language proficiency, yet its impact on overall proficiency and interest in EFL appears limited and context dependent. As San Isidro and Pérez Cañado (Reference San Isidro, Pérez Cañado, Banegas and Zappa-Hollman2023, p. 279) point out, these ‘mixed results give rise to the question as to whether it is only the CLIL approach that leads to improved attitudes and motivations, or the pedagogy used, the type of subject or the target language (mainly English)’. As research continues to evolve with more robust designs and longitudinal data, it becomes clear that motivation in CLIL depends on a mix of teaching practices, context, and personal factors, leading to more reflection on how CLIL is used and who benefits most from it.

4.4 Attention to Diversity in CLIL

Diversity in CLIL refers to the various ways in which CLIL programmes address the different needs, backgrounds, and abilities of students. This encompasses a wide range of factors, including cultural backgrounds, SES, gender, abilities, and ethnicities. This approach is visually represented in Figure 2, which illustrates how the DIDI theoretical framework (Pérez Cañado, Reference Pérez Cañado2023) conceptualises diversity as an umbrella term that supports inclusive education for all students, regardless of their SES, educational background, or level of attainment. This notion of diversity is underpinned by the principles of inclusion and differentiation: inclusion of learners at risk of marginalisation and differentiation for learners with varying abilities and backgrounds. Ultimately, this fosters the integration of students from diverse realities, which has the potential to transform educational systems and models.

Figure 2

The DIDI framework

Figure 2 Long description

A conceptual diagram illustrating the DIDI framework, which presents diversity in CLIL as an overarching concept essential for inclusive education. The framework identifies multiple dimensions of student diversity, including cultural backgrounds, socioeconomic status (SES), gender, abilities, and ethnicities. It emphasises two foundational principles: inclusion, which focusses on supporting learners at risk of marginalisation, and differentiation, which involves adapting teaching to meet learners’ varied abilities and backgrounds.

The diagram shows that embracing diversity through these principles fosters the integration of students from a wide range of social and educational realities. The framework also links inclusion in education with social justice, highlighting CLIL’s potential to promote equity by making educational opportunities accessible to all students, regardless of their backgrounds or academic abilities. Additionally, the figure contextualises ongoing debates about CLIL’s selective nature and the risk of reinforcing educational inequalities, underscoring the importance of designing programmes that are equitable and inclusive.

(based on Pérez Cañado, 2023)

Inclusion in education is also closely linked to social justice (Artiles, Harris-Murri, & Rostenberg, Reference Artiles, Harris-Murri and Rostenberg2006; DeMatthews & Mawhinney, Reference DeMatthews and Mawhinney2014; Polat, Reference Polat2011). The intersection between CLIL and social justice has attracted increasing attention, particularly regarding its potential to promote equity and inclusion in education. As CLIL programmes have become more widespread, attention to diversity within these classrooms has emerged as a critical area of research. This is especially relevant given that CLIL has sometimes been viewed as elitist or segregationist (Broca, Reference Broca2016; Bruton, Reference Bruton2011, Reference Bruton2013, Reference Bruton2015, Reference Bruton2019; Paran, Reference Paran2013). For instance, in her survey, Broca (Reference Broca2016) reports that CLIL students believe their programmes are selective and tend to exclude students with lower academic abilities. Other authors, such as Bruton (Reference Bruton2013), argue that the selective nature of CLIL programmes may exacerbate educational inequalities, as less privileged students may not have equal access to these opportunities, thereby widening the gap between socioeconomic groups.

CLIL programmes are therefore sometimes perceived as elitist due to selection biases, with SES being a significant predictor of participation, often favouring socially privileged learners. Indeed, several studies indicate that SES is an important factor influencing learners’ participation in CLIL programmes. In some cases, students from higher SES backgrounds are more likely to enrol in CLIL, suggesting a selection bias towards more advantaged learners. For example, Van Mensel, Hiligsmann, Mettewie, and Galand (Reference Van Mensel, Hiligsmann, Mettewie and Galand2020) show that CLIL programmes in French-speaking Belgium are particularly attractive to socially privileged audiences, with SES being the main predictor of selection, compared to other variables such as non-verbal intelligence. Moreover, Dutch CLIL programmes appear to be more selective than English CLIL programmes in this context. Caira, Surmont, and Struys (Reference Caira, Surmont and Struys2024) further present evidence that SES and school size are strong predictors of the presence of English CLIL programmes in Belgium, contributing to concerns about educational equity.

However, other authors (e.g. Ainsworth & Shepherd, Reference Ainsworth and Shepherd2017; Lorenzo, Granados, & Rico, Reference Lorenzo, Granados and Rico2021; Pérez Cañado, Reference Pérez Cañado2020; Rascón Moreno & Bretones, Reference Rascón Moreno and Bretones Callejas2018) suggest that while certain socioeconomic variables influence language instruction in both CLIL and non-CLIL contexts, the effect may be less pronounced in CLIL settings. The ‘levelling effect’ of CLIL is evident in its capacity to reduce educational disparities related to SES (Iwaniec & Halbach, Reference Iwaniec and Halbach2021; Rascón Moreno & Bretones, Reference Rascón Moreno and Bretones Callejas2018), as well as other factors such as rural-urban divides (Pavón Vázquez, Reference 61Pavón Vázquez2018) and gender differences (Martínez Agudo, Reference Martínez Agudo2021).

Notably, Halbach and Iwaniec (Reference Halbach and Iwaniec2020) and Iwaniec and Halbach (Reference Iwaniec and Halbach2021) confirm that CLIL helps reduce SES differences among students and promotes high levels of motivation overall by creating a learning environment that supports autonomy, competence, and relatedness. This suggests that CLIL can be effective in disadvantaged contexts or less academic educational tracks (Denman, Schooten & Graaff, Reference Denman, van Schooten and de Graaff2022; Grandinetti, Langellotti, & Ting, Reference Grandinetti, Langellotti and Ting2013), although this is not always the case.

Consequently, the contribution of CLIL to inclusion and equity has been both questioned and explored through conceptual and empirical studies across different contexts and educational levels (Llinares & Cross, Reference Llinares and Cross2022). The central question remains whether this educational model can genuinely contribute to, or hinder, equitable and inclusive education. For example, in their study on diversity, Nikula, Skinnari, and Mård-Miettinen (Reference Nikula, Skinnari and Mård-Miettinen2022) report that Finnish CLIL teachers and students emphasise equality (i.e. the same for all) in teaching and assessment, while equity (i.e. personalised support) receives less attention, leading to tensions between maintaining equality and addressing individual needs.

In a comparable vein, research from the German context by Siepmann, Rumlich, Matz, and Römhild (Reference Siepmann, Rumlich, Matz and Römhild2021) shows through multi-perspective studies that although diversity is often acknowledged in CLIL classrooms, challenges persist in effectively addressing a diverse student population. A similar picture emerges from studies conducted in Spain (Casas Pedrosa & Rascón Moreno, Reference Casas Pedrosa and Rascón Moreno2021; McClintic, Reference McClintic2022), where addressing diversity in CLIL is considered important in areas such as linguistic aspects, methodology, materials and resources, assessment, and teacher coordination and development. However, Spanish CLIL teachers still face significant obstacles and limitations in this regard.

In all cases, CLIL provision must be redesigned to accommodate educational differentiation (Madrid & Pérez Cañado, Reference Madrid and Pérez Cañado2018; Pérez Cañado, Reference Pérez Cañado2021), by addressing special needs and ensuring it is genuinely inclusive for all learners. Research further underscores the importance of developing and implementing diversity-sensitive pedagogical practices, such as scaffolding and learner-centred designs, to foster academic success for all students (Bauer-Marschallinger, Dalton-Puffer, Heaney, Katzinger, & Smit, Reference Bauer-Marschallinger, Dalton-Puffer, Heaney, Katzinger and Smit2021; Pérez Cañado, Reference 62Pérez Cañado2024).

This synthesis of the role of CLIL in promoting equity and inclusion reveals mixed results, highlighting both the opportunities and the challenges of ensuring fair access to quality education through CLIL. While CLIL programmes strive to address diversity through various pedagogical strategies, significant challenges remain in effectively meeting the diverse needs of learners. More effective differentiation, improved teacher training, and a better balance between equality and equity are essential to ensure that all learners benefit from CLIL. Furthermore, greater (inter)cultural and multilingual awareness is crucial to making CLIL provision more inclusive (Garcia, Reference Garcia2012; Porto, Reference Porto, Banegas and Zappa-Hollman2023).

As this remains a relatively new area of research, further studies are needed to explore the challenges and strategies involved in ensuring that CLIL is inclusive and equitable for all learners. Some of these strategies include differentiation techniques, inclusive pedagogical approaches, multimodal communication, and collaborative professional learning. For example, as Liu and Lin (Reference Liu and Lin2021) argue, reconceptualising language in CLIL as a multimodal dimension and adopting a pedagogy of multiliteracies can help address diversity and foster a more equitable classroom and school culture.

Additionally, an integrated approach that involves teachers as researchers, working in partnership with learners, can empower diverse students to participate meaningfully and feel valued, thereby promoting social justice and inclusion (Banegas & Ruiz de Zarobe, Reference Banegas, Ruiz de Zarobe, Ruiz de Zarobe and Banegas2024; Coyle, Bower, Foley, & Hancock, Reference Coyle, Bower, Foley and Hancock2021). Pérez Cañado (Reference 62Pérez Cañado2024) also identifies several critical factors for achieving inclusion in CLIL programmes. These include aligning teacher and student perspectives to develop effective inclusive strategies, as well as addressing persistent challenges such as allocating time for coordination and adequately preparing language assistants.

CLIL research thus highlights a complex interplay between elitism and diversity. While concerns remain about socioeconomic selection biases contributing to an elitist model, significant efforts are being made to render CLIL more inclusive. Both teachers and learners acknowledge the need for more personalised support and effective differentiation techniques to accommodate diverse student populations. Ongoing research and the development of inclusive practices and resources are essential to ensure that CLIL can meet the needs of all learners.

4.5 Summary

Early research on CLIL focussed primarily on language learning outcomes, while more recent studies emphasise CLIL’s unique educational approach, which aims to integrate content and language acquisition. Findings indicate that CLIL enhances second language learning, student motivation, and engagement. Other aspects, such as attention to diversity, have also gained importance. Overall, CLIL appears to be an effective method for integrating language and content learning without compromising students’ content knowledge or L1 development. As the next section will show, the potential role of the L1 in CLIL settings is increasingly acknowledged, challenging traditional monolingual immersion ideologies and encouraging a more flexible and balanced approach.

5.1 Translanguaging and CLIL

The concept of translanguaging originates in the Welsh notion of trawsieithu (Williams, Reference Williams, Williams, Lewis and Baker1996) and traces back to English–Welsh bilingual education in the 1980s (Lewis, Jones, & Baker, Reference 56Lewis, Jones and Baker2012). Translanguaging can refer both to the spontaneous alternation between languages and to a pedagogical approach in which teachers deliberately support this practice (see Section 5.2 for a more comprehensive definition of the concept).

This approach has gained traction in multilingual education settings worldwide, though it has also sparked some controversy regarding the differences between translanguaging and more traditional concepts such as codeswitching. Both concepts are central to the study of multilingualism, but according to some authors (see, for example, Anderson, Reference Anderson2024 and Treffers-Daller, Reference Treffers-Daller2024, for alternative views), they differ in their theoretical underpinnings and practical applications. Codeswitching is traditionally understood as alternating between two distinct language systems, often marked by clear boundaries between the languages used, whereas translanguaging is seen as a holistic practice in which bilinguals draw from a single, integrated linguistic repertoire without strict boundaries between languages (Cenoz, Reference Cenoz2017; Lin, Reference Lin and Vaish2020).

Translanguaging research emphasises the dynamic and fluid nature of bilingual communication, viewing it as a natural and integrated part of bilingual speakers’ linguistic competence. Additionally, there are two approaches to translanguaging: one advocates softening boundaries in bilingual education, while a second ‘strong’ version postulates a single linguistic repertoire for bilingual speakers (Garcia & Lin, Reference Garcia, Lin, García, Lin and May2016). Beyond these considerations, translanguaging implies ‘the deployment of a speaker’s full linguistic repertoire without regard for watchful adherence to the socially and politically defined boundaries of named (and usually national and state) languages’ (Otheguy, Garcia, & Reid, Reference Otheguy, Garcia and Reid2015, p. 284).

Setting aside the dichotomy between codeswitching and translanguaging (and related concepts, see, for instance, Marshall & Moore, Reference Marshall and Moore2018 and Li, Reference Li2018), we can appreciate how translanguaging is rooted in the so-called ‘multilingual turn’ (Canagarajah, Reference Canagarajah2013; May, Reference May2013), which refers to a significant shift in language education that challenges traditional monolingual norms and embraces multilingualism as a resource, focussing on the dynamic and complex nature of language learning and use.

In CLIL settings, translanguaging has mainly been developed for instructional purposes as a way to create an engaging learning environment that enhances students’ acquisition of content knowledge and language skills. In CLIL research, the field has evolved from an initial phase where studies focussed on the use and role of the L1 (for example, Lasagabaster, Reference Lasagabaster2013; Lin, Reference Lin2015; Méndez García & Pavón Vázquez, Reference Méndez García and Pavón Vázquez2012) to a later phase with a clear focus on translanguaging itself. In this second group, studies report students using their full linguistic repertoire, either spontaneously or pedagogically, which leads to better understanding and retention of subject matter. Spontaneous translanguaging refers to learners’ natural use of all their languages to make meaning or communicate with peers, often emerging informally during classroom interactions. In contrast, pedagogical translanguaging is deliberately planned and facilitated by teachers as part of instruction, involving structured opportunities for students to draw on their whole linguistic repertoires to support learning objectives.

Among studies investigating translanguaging, Bieri (Reference Bieri2018) conducted a qualitative analysis of transcripts from CLIL (English) and non-CLIL (German) biology lessons in Switzerland. The findings revealed that using students’ source languages to explain technical vocabulary was particularly effective for negotiating meaning. Interestingly, the teacher who most strongly advocated for an English-only policy in the classroom engaged in translanguaging more frequently than others, suggesting that teachers may be unaware of their own translanguaging practices, or that their beliefs do not always align with their classroom practices (see also, for instance, Arocena, Reference Arocena2017 and Gorter & Arocena, Reference Gorter and Arocena2020). In the Basque Country, Leonet, Cenoz, and Gorter (Reference Leonet, Cenoz and Gorter2020) reported on a study of cognate identification and cognate awareness conducted in a multilingual primary school (Basque, Spanish, and English). The results indicated that pedagogical translanguaging positively influenced morphological awareness and the multilingual learners’ perception of their multilingual repertoire.

Nikula and Moore (Reference Nikula and Moore2019), in their exploratory study in Austria, Finland, and Spain, highlighted that translanguaging in CLIL contexts can be a valuable tool for bilingual learning, with pedagogical and interpersonal motivations influencing language choices in CLIL classrooms. The study suggests that L1 should be appreciated as a valuable tool in bilingual learning situations, advocating for increased awareness of its benefits. Other authors, such as Pavón Vázquez and Ramos Ordoñez (Reference Pavón Vázquez and Ramos Ordóñez2019), argue that the use of the L1 in CLIL classes does not negatively affect content learning, but it reduces the time students devote to using the L2.

Several researchers in Asia have reported on the beneficial use of translanguaging. Lin and He (Reference Lin and He2017) showed how translanguaging occurred naturally in CLIL classrooms despite dominant monolingual instruction policies, as students and teachers engaged in meaning-making about lesson topics. Wu and Lin (Reference Wu and Lin2019) also demonstrated how translanguaging and trans-semiotising practices (i.e. the process of making meaning by shifting between or combining different modes of communication, such as language, images, gestures, and symbols) in a CLIL biology class in Hong Kong positively impacted students’ ongoing co-construction of knowledge and understanding of biology concepts. Liu (Reference Liu2020) applied the same theory of translanguaging and trans-semiotising in CLIL classrooms to challenge the dominance of English and contest cultural patterns by orchestrating Cantonese and English, formal and social languages, visual elements, and physical items. Finally, Sohn, dos Santos, and Lin (Reference Sohn, dos Santos and Lin2022) asserted that translanguaging pedagogies in CLIL involve a critical integration of content and language learning in multilingual settings, challenging English-only pedagogies. It appears that CLIL can differentiate itself from monolingual L2 immersion education models by being more flexible and balanced in incorporating L1 in CLIL lessons.

Beyond the benefits of these multilingual practices, another research strand has examined student and teacher attitudes towards this instructional approach. Most studies show that students tend to have positive attitudes towards translanguaging, appreciating the flexibility and support it provides in learning both language and content (Rafi & Morgan, Reference Rafi and Morgan2023; Wu & Lin, Reference Wu and Lin2019), even at a very early age (Aleksić & Garcia, Reference Aleksić and Garcia2022; Vega Pérez & Ruiz de Zarobe, Reference Vega Pérez and Ruiz de Zarobe2024).

However, teachers may hold contradictory or negative perceptions of translanguaging due to ideological and sociopolitical factors, such as the prestige of the target language and institutional policies. For example, Karabassova and San Isidro (Reference Karabassova and San Isidro2023) found that Kazakhstani CLIL teachers use translanguaging as scaffolding, transitional practice, and to compensate for their own language proficiency limits in teaching trilingual learners. Rafi and Morgan (Reference Rafi and Morgan2023) showed how combining translanguaging and CLIL in Bangladeshi classrooms improved student engagement and content knowledge but faced ideological challenges stemming from sociopolitical realities. In other studies (e.g. Haukås, Reference Haukås2016; Portolés & Martí, Reference Portolés and Martí2018; Tarnanen & Palviainen, Reference Tarnanen and Palviainen2018), teachers view multilingualism as a potentially positive asset but are reluctant to use it in the classroom or require time to become familiar with the approach (Galante, Reference 52Galante2020).

Overall, translanguaging as a theoretical and instructional approach involves strategies that integrate multiple languages to develop multilingual repertoires and metalinguistic awareness. It promotes support for and development of all languages used by learners (Cenoz & Gorter, Reference Cenoz and Gorter2021). The research presented here shows that translanguaging in CLIL offers both pedagogical and interpersonal benefits that improve student engagement and comprehension. Translanguaging is learner-centred and, as such, should tap into the entire multilingual and multimodal linguistic repertoires of learners, allowing them to benefit from their multilingualism. However, translanguaging also faces challenges related to ideological complexities and monolingual viewpoints; teachers’ perceptions may vary, highlighting the need for awareness and training (Cenoz & Santos, Reference Cenoz and Santos2020).

Another concern relates to the difficulty of pedagogically developing some principles and strategies of translanguaging. Beyond the strategic use of the L1 by teachers and students to reinforce content learning, deepen understanding, and engage students more effectively, alternating between input and output languages within the same lesson can promote metalinguistic awareness and help students cope with complex academic language (Cenoz & Gorter, Reference Cenoz and Gorter2022). Another possibility is the incorporation of multimodal and semiotic resources, such as gestures, visual aids, and other semiotic tools alongside translanguaging practices, to support meaning-making and enhance comprehension (He & Lin, Reference He and Lin2021; Wu & Lin, Reference Wu and Lin2019). In the next section, we will address multimodality and CLIL in more detail.

5.2 CLIL and Multimodality

Multimodal approaches in CLIL involve integrating various semiotic resources to support both content and language learning. These resources include visual aids, gestures, and digital tools, which help make complex concepts more accessible to students. In the previous section, we already mentioned research focussing on multimodality, as several studies on translanguaging also incorporate the concept of trans-semiotising (He & Lin, Reference He and Lin2021; Lin & He, Reference Lin and He2017; Liu, Reference Liu2020; Wu & Lin, Reference Wu and Lin2019). While translanguaging involves the fluid use of multiple languages beyond traditional linguistic boundaries, trans-semiotising specifically refers to the use of various semiotic resources, such as visual, gestural, or other multimodal elements, alongside linguistic ones to collaboratively co-construct meaning. This combination enriches the learning process, allowing students to express and understand content in diverse and dynamic ways.

Some authors (Li, Reference Li2018; Li & Garcia, Reference Li and Garcia2022; Tai, Reference Tai2023; Tai & Li, Reference Tai and Li2024) even argue that the very concept of translanguaging encompasses both constructs: ‘Translanguaging offers a practical theory of language that sees the latter as a multilingual, multisemiotic, multisensory, and multimodal resource that human beings use for thinking and for communicating thought’ (Li, Reference Li2018, p. 26). According to these scholars, translanguaging as a theory (i.e. translanguaging pedagogy, rather than pedagogical translanguaging) highlights the multimodal and multisensory nature of multilingual users’ social interactions, going beyond named languages and acknowledging the diverse linguistic and cultural practices of multilingual students (Li & Garcia, Reference Li and Garcia2022). In any case, multimodal approaches have been shown to positively impact students’ comprehension and engagement in CLIL classrooms, where semiotic resources facilitate understanding of content delivered in the additional language.

Drawing on various theoretical perspectives, some research on CLIL has examined classroom interaction, focussing on both the use of multimodal resources and the teacher’s role in fostering participation and comprehension. Among these approaches is Multimodal Conversation Analysis, a research framework that explores how modalities such as gestures and written texts are employed as resources for interaction in CLIL settings. This approach underscores the importance of multimodal resources in ensuring understanding and encouraging student participation (Evnitskaya & Jakonen, Reference Evnitskaya, Jakonen, Llinares and Morton2017).

In Finland, Kääntä, Kasper, and Piirainen-Marsh (Reference Kääntä, Kasper and Piirainen-Marsh2018) applied Multimodal Conversation Analysis to investigate how a science teacher in a CLIL programme employed various definitional practices in an English-medium physics class. Their study highlights the value of coordinating multilingual and multimodal practices to effectively define and contextualise physical phenomena. Similarly, in an exploratory study, Evnitskaya and Morton (Reference Evnitskaya and Morton2011) demonstrated how students’ willingness to participate in classroom interaction fluctuated, influenced by factors such as attentiveness, turn-taking, and participation roles.

Within the Systemic Functional Multimodal Discourse Approach, Fernández-Fontecha, O’Halloran, Wignell, and Tan (Reference Fernández-Fontecha, O’Halloran, Wignell and Tan2020) showed that visual thinking methodologies can be effective in science education. Moreover, incorporating visual and other semiotic resources can scaffold both language and content learning, making complex concepts more accessible and supporting translanguaging practices in the classroom. Teachers’ use of multimodal resources in dialogic discussions can also mediate and remediate content, offering students opportunities to appropriate both language and content.

In this vein, Amondarain-Garrido and Ruiz de Zarobe (Reference Amondarain-Garrido and Ruiz de Zarobe2024) analysed the multimodal discourse of three primary school CLIL teachers in science classes. Using multimodal interaction analysis, they demonstrated how teachers used multimodal resources to support language, assist students with various discourse functions, and construct a multimodal system of meaning to aid learning in the CLIL science classroom.

In Hong Kong, Wu and Lin (Reference Wu and Lin2019) demonstrated how translanguaging and trans-semiotising practices in a CLIL biology class positively impacted students’ construction of knowledge and understanding of biology concepts. He and Lin (Reference He and Lin2021) further explored how these practices facilitate the expansion of students’ communicative repertoires, enabling them to adapt to and internalise unfamiliar registers, which in turn supports mastery of both the target language and subject content. Their research also highlighted how teachers can design learning environments that incorporate translanguaging and trans-semiotising while also providing space for the use of the target language. These findings offer valuable insights for CLIL curriculum design and teacher professional development.

Additionally, Liu and Lin (Reference Liu and Lin2024) investigated how co-teachers employed translanguaging and trans-semiotising strategies in CLIL lessons for primary students with dyslexia in Hong Kong. Their study underscored the potential of translanguaging to support learners with special needs, particularly in facilitating their use of the target language, thereby emphasising the value of inclusive and flexible teaching practices in CLIL classrooms.

These studies demonstrate that translanguaging and trans-semiotising practices enable students to draw on a wide range of linguistic and semiotic resources to construct and express their understanding. Such practices align with Lin’s Multimodality Entextualisation Cycle (MEC) (Reference Lin2015, Reference Lin and Lin2016), which offers a framework for analysing how multiple modes of communication, verbal, visual, and gestural, interact to create meaning. In CLIL settings, where content and language are integrated, these multimodal practices allow students to engage with subject matter in diverse ways, thereby enhancing both comprehension and participation. The MEC’s concept of entextualisation emphasises how knowledge is conveyed not through a single language, but through a dynamic combination of semiotic modes. This process enables students to expand their communicative repertoires and participate in more flexible, context-sensitive learning experiences.

In sum, research on multimodality in CLIL highlights its positive impact on student engagement and understanding, supporting more interactive and inclusive classroom practices (see Ruiz de Zarobe & Querol-Julián, Reference Ruiz de Zarobe and Queról-Julián2025). These findings call for reconceptualising ‘language’ in CLIL as a multimodal construct that integrates various semiotic modes beyond verbal language (Liu & Lin, Reference Liu and Lin2021; Lo, Reference Liu and Lo2024). Consequently, providing educators with specialised training in multimodal resources is important to enhance classroom interaction. Additionally, curricula should incorporate translanguaging spaces (He & Li, Reference He and Lin2021), where students can draw on their full multimodal repertoires, as well as ‘breathing spaces’, intentional pauses that allow learners to utilise their complete linguistic resources to deepen understanding and support multilingual development while prioritising the additional language (Cenoz & Gorter, Reference Cenoz and Gorter2021). Integrating such teacher training and curriculum designs can better support the benefits of multimodal practices in CLIL classrooms.

5.3 Summary

This section has examined the role of translanguaging and multimodality in CLIL contexts. After defining both concepts, which are often closely intertwined, we reviewed research highlighting how these pedagogical practices function as scaffolding tools to help students make sense of complex content through a range of semiotic modes and multilingual resources. These approaches contribute to the development of more inclusive, engaging, and interactive classroom environments. As CLIL continues to evolve, translanguaging and multimodality offer valuable strategies for addressing the diverse needs of learners in multilingual educational settings.