This study investigated whether L2 processing of derived words engages biphasic morphological decomposition, comprising morpho-orthographic segmentation followed by morpho-semantic integration, as L1 processing does. Using an overt priming paradigm (SOA = 300 ms), ERP responses were compared across morphological (e.g., farmer–farm), orthographic (e.g., cashew–cash) and semantic (e.g., doctor–nurse) priming conditions in native and L2 speakers. Results revealed that both language groups exhibited distinct priming effects for morphologically related prime–target pairs across the early and late N400 windows, reflecting morpho-orthographic segmentation and morpho-semantic integration, respectively, rather than additive effects of form and meaning overlap. However, the late negativity effect, reflecting intensified lateral inhibition among similar orthographic representations, was observed during orthographic priming only in native speakers, suggesting less efficient inhibitory control in L2 processing. These findings are discussed within the framework of the Shallow Structure Hypothesis, which has provided a theoretical basis for many previous L2 studies of derived-word processing.

This study explores the association between school-based foreign language (FL) instruction and mathematical achievement among 15-year-old students, using data from the 2018 Programme for International Student Assessment (PISA). Two complementary analyses were conducted: a large-scale model (n = 300,656) examining the relationship between time spent in FL learning and maths performance across 73 countries and a machine learning (ML) approach (random forest (RF); n = 53,459) identifying specific programme features that most strongly influence this relationship. Results show that longer exposure to FL instruction was associated with a modest but statistically robust increase in maths scores (β = 0.08, p < .001), even after controlling for socioeconomic and contextual factors. Among programme characteristics, the integration of multicultural curricula emerged as a prominent predictor of higher maths performance. These findings indicate that sustained, culturally enriched FL learning is positively associated with numeracy outcomes, with implications for equity in academic achievement and cross-disciplinary performance.

Cross-language figurative meaning activation in idiom processing has been observed in primed lexical and semantic decision tasks, but not in text reading. To study first-language figurative idiom meaning activation in second-language reading, we created and tested a novel contextual idiom-priming paradigm and conducted an eye-tracking experiment with Chinese–English immersion and non-immersion bilinguals, and English-speaking controls. Three counterbalanced conditions were created: in English texts, the meaning probe was preceded by a close or paraphrased translation of a related Chinese-only idiom, or an unrelated phrase. The processing of the probe was influenced by figurative meanings of Chinese-only idioms for both groups of bilinguals, but not for monolingual controls, evidencing non-selective language processing beyond single words. There was no difference in the patterns of activation between close and paraphrased translations, suggesting that exact lexical overlap may not be necessary for cross-language activation of idioms. Different processing patterns were observed for immersion and non-immersion bilinguals.

In a socio-interactive context, bilinguals effortlessly plan their language appropriately. This study explores how high-literate and low-literate bilinguals plan their language when interacting with interlocutors with varied second language (L2) proficiency presented in an interactive context. Participants named objects in the presence of interlocutors with varying proficiency, which were presented in the background as visual-world stimuli. Results indicate that bilingual participants’ language choices and proportion of fixations were modulated by their level of literacy and the interlocutors’ language profiles. High-literate bilinguals chose to name in L2, and while doing so, they looked at high-L2-proficient interlocutors. Meanwhile, low-literate bilinguals looked at low-L2-proficient interlocutors and named in first language (L1) more often times than in L2. This indicates that bilinguals’ literacy level is not determined solely by their language choice but also by their sociolinguistic processing when interacting with interlocutors with varied L2 proficiencies.

The roles of structural and lexical similarity in cross-linguistic influence in the L3 at higher proficiency levels are under researched. This study investigates the L3 Norwegian of such speakers. In alignment with the Linguistic Proximity Model (Westergaard et al., 2017), we assume that L3 structures are initially weak representations, becoming increasingly target-like with further input and use. We investigate what target this represents – the prescriptive rules of the language or movement towards L1-like use from community interaction and input. The properties investigated are the indefinite article and third person and reflexive possessives, by L1 Polish–L2 English and L1 English speakers. These categories provide fertile ground for investigation due to the (dis)similarities with the target language. The methodology consisted of an Acceptability Judgement Task. Results indicated possible structural-similarity based CLI and adherence to grammatical rules in intermediate-to-advanced proficiency L3ers – though this does not necessarily equal L1-like choices.

This study investigates the relationship between bilingualism, language use, aging, and interference control using the Color–Word Stroop test task. We examined 158 highly proficient Basque–Spanish bilinguals and 84 Spanish monolinguals (aged 30–80 years) to test whether interference control declines with age and whether bilingual adaptations depend on language use frequency. Language experience was assessed using an adapted Language and Social Background Questionnaire and Color–Word Stroop test interference scores were analyzed by regression models. Results showed that interference control declines with age. Group-level differences between bilinguals and monolinguals were not significant once education was included as a covariate, although a small marginal advantage for bilinguals emerged when using education-adjusted T-scores. Within the bilingual group, higher use of the minority language (Basque) in social contexts was associated with significantly better interference control. Social language use showed a stronger relationship with interference control than home use. These findings highlight that bilingual advantages are not uniform but depend on language use frequency and context, contributing to understanding how bilingual experience shapes cognitive control across the lifespan.

Research teams studying bilingualism often focus on a specific population of bilinguals, which can limit the generalizability of their findings. This study explored how U.S. adolescents who speak a non-English language vary in their language experiences and cognition using data from the Adolescent Brain Cognitive Development (ABCD) study. The sample included 6683 English monolinguals, 1138 heritage bilinguals, 592 dual language education (DLE) bilinguals and 1751 other bilinguals. SES varied across groups: sequential bilinguals (i.e., DLE and other bilinguals) had higher parental education and income than monolinguals, while heritage bilinguals had the lowest SES. Sequential bilinguals reported higher English proficiency and greater English use with family and friends than heritage bilinguals. Sequential bilinguals initially outperformed monolinguals on cognitive tasks, who in turn outperformed heritage bilinguals. However, these differences disappeared once SES was controlled. Findings highlight the importance of considering SES and language experiences when studying bilingualism’s cognitive effects and help explain inconsistencies in prior research.

The influence of one of a bilingual’s languages on the other is known as cross-linguistic influence (CLI). In grammatical gender acquisition, CLI can occur during gender discovery, assignment and agreement. The present study investigates CLI in Dutch as a heritage language, a language with a non-transparent gender system, in two groups of bilingual children. One (i.e., Dutch-German bilingual children) is acquiring languages with similar gender systems and the other (i.e., Dutch-French bilingual children) is acquiring languages with more distant gender systems. We found CLI in gender discovery, gender assignment and gender agreement for the Dutch-German group but not for the Dutch-French group. Moreover, CLI simultaneously facilitated and hindered gender acquisition within the children, depending on the gender congruency of the nouns. This suggests co-activation of grammatical gender values in bilingual children. The findings help us better understand when cross-linguistic influence takes place and how it affects acquisition in bilingual children.

This study examined whether self-assessed multilingual proficiency and use of additional languages predict individual differences in inhibitory control (IC) and mind wandering (MW) among UK university students. Sixty-five participants completed a Go/No-Go task measuring response inhibition and the BMW-3 questionnaire, which assessed unintentional, intentional and meta-awareness dimensions of MW. Multilingualism was operationalised using a continuous composite index integrating self-rated proficiency and daily use of non-native languages. The index scores were not significantly associated with response inhibition or meta-awareness. However, higher multilingual proficiency index scores were significantly associated with lower levels of unintentional MW. These findings suggest that, moving beyond categorical comparisons, greater self-reported multilingual proficiency and use of additional languages may support the regulation of internally directed thought, rather than externally triggered IC. Implications for future research and potential applications in education and attention-related interventions are discussed.

The moral foreign language effect (MFLE) suggests that using a second language promotes utilitarian moral decisions, though its robustness and underlying mechanisms remain debated. This study investigated the MFLE and its potential moderators, including cognitive control, emotional distress and contextual variability (operationalized as victim vulnerability through narrative cues signaling physical fragility), among 255 Chinese-English bilinguals who judged moral dilemmas in either their native or second language. Contrary to prior findings, no significant MFLE emerged, nor did cognitive control or emotional distress alone moderate moral judgments. In contrast, victim vulnerability showed a robust main effect, with higher vulnerability increasing utilitarian responses. Moreover, this effect interacted with emotional distress: it was pronounced under low distress but diminished under high distress. These findings challenge the generalizability of the MFLE and highlight the pivotal influence of emotional and contextual factors, particularly emotional arousal and perceived victim vulnerability, on moral judgments across languages.

This study examines when and how second language (L2) learners begin to exhibit sensitivity to key factors influencing the choice between the English double object and prepositional object constructions. While previous research has shown that such choices in native speakers are influenced by such factors as animacy, pronominality and verb bias, little is known about the developmental timing of these effects in L2 production. Using 5,785 dative constructions from a large-scale learner corpus, we analyzed how these variables interact with learners’ proficiency levels across 23 verbs. We found that learners showed systematic sensitivity to all of these factors, including statistical verb bias derived from a native speaker corpus (Corpus of Contemporary American English), at much earlier stages than previously suggested. These results suggest that learners may possess a cognitive bias that maps preexisting conceptual structures onto linguistic constructions, reflecting more than mere statistical learning.

Dual subtitles, combining captions (audio transcription) with subtitles translated into another language, are increasingly used in language learning. However, how they shape visual attention remains unclear. In the present experiments, we tracked the eye movements of Spanish–English bilinguals, as they viewed instructional videos with either no subtitles (Experiment 1) or dual subtitles (Experiment 2), manipulating subtitle position and audio language. Without subtitles, L1 audio focused gaze on the speaker’s eyes, while L2 audio distributed it between the eyes and mouth. With dual subtitles, gaze shifted strongly to the text, with a preference for the top line, which attracted more viewing time regardless of language. Viewers selectively attended to the line matching the audio. Comprehension improved for L2 audio with subtitles, while L1 comprehension was unaffected. Our findings demonstrate that display layout and language alignment jointly govern attentional allocation in bilingual viewing, with direct implications for L2 instructional design.

Bilinguals vary in their daily-life language use and switching behaviours, which are also frequently studied in relation to other processes (e.g., executive control). Measuring daily-life language use and switching often relies on self-reported questionnaires, but little is known about the validity of these questionnaires. Here, we present two studies examining test–retest reliability and validity of language-use questionnaires (relative to Ecological Momentary Assessment, Study 1) and language-switching questionnaires and tasks (relative to recorded daily-life conversations, small-scale Study 2). Test–retest reliability and validity of the LSBQ (Anderson et al., 2018) were high and moderate, respectively, suggesting this questionnaire can capture daily-life language use well. Although only examined with a small sample size, Study 2 suggested relatively low validity of most language-switching questionnaires, with short language-production tasks potentially offering a more valid assessment. Together, these studies suggest that tools are available to reliably capture language use and switching with (a certain degree of) validity.

Previous research has highlighted that supplementing standard group-level event-related potential analyses with assessments of individual variation can enhance our understanding of language-related brain activity. The present study pursues this approach by examining bilingual speakers’ brain responses to morphologically complex word forms in both their native (German, L1) and their second language (English, L2). We tested 108 bilingual speakers using an ERP violation paradigm examining overapplications of regular verb inflections (‘regularizations’) and of irregular ones (‘irregularizations’). We found a striking L1/L2 contrast within the same bilingual speakers, a left-anterior negativity for regularizations in the L1 and a positivity (P600) for both violation types in the L2. Consistent with previous research, individuals’ brain responses were found to vary along negativity-/positivity-dominant effects. However, the crucial L1/L2 contrast in participants’ brain responses to regularizations was stable across individual differences. We conclude that linguistic constraints, that is, violation type and language status (L1 vs. L2), limit individual variability.

Learning a second language (L2) is challenging partly due to perceptual strategies inherited from learners’ first language. For example, speakers of tone languages like Mandarin over-use pitch in English prosody perception and production. We developed a novel training paradigm to help Mandarin learners adopt more native-like strategies by enhancing their use of duration relative to pitch cues during prosody categorization. After prosody training, participants used duration more during phrase boundary categorization but showed no clear change for contrastive focus and lexical stress, suggesting that cue weighting training is most effective when targeting a feature’s primary cue. The control group, who practiced English vocabulary, relied more on pitch in lexical stress categorization and phrase boundary production after training, suggesting that without targeted instruction, listeners default to existing strategies. Our findings demonstrate that although default strategies in L2 speech perception are difficult to resist, lifelong perceptual habits can be adjusted with training.

This study examined the acoustic realization of focus in Cantonese-English bilingual autistic children’s first language (L1) Cantonese, compared to bilingual typically developing (TD) children and adults, and explored the effects of bilingualism on the production. Results from an elicitation task showed that bilingual autistic children primarily relied on duration to mark focus in L1 Cantonese, similar to adults, but exhibited weaker use of pitch and intensity compared to bilingual TD children. Second language (L2) English exposure and proficiency did not influence focus marking in bilingual autistic children likely due to their later and reduced English exposure compared to TD children. Conversely, bilingual TD children’s prosodic use was modulated by English exposure and proficiency. These findings reveal that bilingualism does not hinder autistic children’s prosodic focus production in their L1 Cantonese and highlight distinct bilingualism effects on prosodic focus production in autistic and TD children.

It has been argued that lexical access in bilinguals is language nonselective. However, little is known about how the input modality (spoken or written) affects cross-language activation during listening and reading. The current study characterizes the nature of within- and cross-language competition for spoken and written words in adults who are bilingual and biliterate in Spanish and English. Using a recently developed cross-modality version of the Visual World Paradigm, we found that competition differs for spoken and written words. For spoken words, the auditory stimulus unfolds overtime giving an additional boost to within- and cross-language competition. Conversely, written words can be seen at once, and thus, incremental processing is less of a factor, resulting in less competition within a language and no competition across languages. The findings show that word recognition is fundamentally language nonselective but can behave in selective ways depending on the modality of the input and language experience.

Word frequency databases like SPALEX and SUBTLEX-ESP treat Spanish as a uniform language, but prior studies and an initial survey (Experiment 1) revealed significant lexical differences between Spanish in Spain and Latin American countries, especially Chile. To establish subjective frequencies of Spanish word usage, an extended survey (Experiment 2) was conducted with Chilean participants, categorizing words by usage area: General, Spain, Chile, and Latin America. Consistent with the initial survey, Chilean participants assigned subjective higher ratings to General and Chilean words. In a lexical decision experiment (Experiment 3), participants responded faster and more accurately to words from these categories. Using survey data, simulations with Multilink+ (Experiment 4) revealed that subjective word ratings better predicted Chilean reaction times than frequencies from existing databases. These findings emphasize the need to address Spanish dialectal differences in research, with word ratings offering a more accurate measure of region-specific lexical nuances than current databases.

This study investigates an asymmetry in (Mandarin) Chinese-English word-internal code-switching: while Chinese inflectional morphemes readily attach to English verbs, Chinese derivational morphemes are consistently rejected when combined with English lexical bases. This pattern raises questions about how the free morpheme constraint should be formulated in bilingual grammar. Building on the phonetic form (PF) interface condition, as proposed in MacSwan’s [Generative approaches to codeswitching. In B. E. Bullock & A. J. Toribio (Eds.), The Cambridge handbook of linguistic code-switching (pp. 309–335). Cambridge University Press (2009)], we argue that the asymmetry is best explained in a lexicalist model that permits post-syntactic affixation. In this approach, inflectional morphology may attach at PF through PF merger, whereas derivational morphology is assembled prior to syntax. The observed asymmetry thus follows from the distribution of morphology across components and the conditions governing the mapping from syntax to phonology. The findings show that derivational timing shapes code-switching, support the viability of lexicalist models that permit post-syntactic affixation, and indicate that word-internal code-switching is permitted under specific interface conditions.

Previous studies suggest that bilinguals can quickly identify the language to which a word belongs in order to suppress a task-irrelevant language. The current study tested whether nontarget language suppression occurs at the lexical and/or semantic levels and whether the degree of processing differs across these representational levels. Spanish–Basque bilinguals classified words by language membership and animacy, and event-related potential (ERP) results demonstrated that task demands to attend to a single target language reduced frequency effects and eliminated concreteness effects for words in the nontarget language. Results support a partially selective mechanism of bilingual language control based on task demands such that words belonging to the nontarget language are only partially processed at the lexical level and are not processed at a deeper semantic level. These findings specify the locus of bilingual language control in comprehension and call for revisions to models of bilingual visual word recognition such as BIA+.