Successful use of word-formation strategies is fundamental for children’s language development and vocabulary expansion (Clark, 2009, First language acquisition. Cambridge University Press). Notably, English-speaking children tend to use compounding (i.e., the joining of two roots/free morphemes) to form new words, a word-formation device highly productive in English. In contrast, Polish-speaking children rely more on derivation (i.e., the addition of an affix/bound morpheme to a root), a device which is highly productive in Polish. Less is known about how bilingual children apply word-formation devices. Thus, monolingual (English) and bilingual (English/Polish) children completed a word-formation task designed to elicit compounding (root, synthetic) and derivation (noun, verb, adjective). Results showed that bilingual children tested in Polish used more derivation and less compounding than children tested in English (monolingual, bilingual). These findings and others are discussed in terms of how bilingual children’s input and testing languages may influence their use of word-formation devices.

This study investigates whether child-directed speech (CDS) exhibits enhanced segmentability compared to adult-directed speech (ADS) and explores how specific linguistic properties of each register influence computational word segmentation performance in Korean. Employing a speaker-matched corpus of naturalistic Korean CDS and ADS, we observed that Korean CDS features shorter utterances and words, lower lexical diversity, fewer hapax legomena and interjections, a greater proportion of onomatopoeia and word play, a higher frequency of one-word utterances, and lower lexical ambiguity than ADS. Computational algorithms revealed significantly higher word segmentation F-scores for CDS than ADS, suggesting that child-oriented linguistic adaptations in CDS facilitate segmentation. This observation is further supported by statistical modelling, which indicates that the enhanced segmentability in CDS is modulated by the linguistic properties of the register. We discuss the nuanced roles of these properties in shaping the performance of segmentation algorithms.

This study examines verbal backchannel behaviour in English children aged 5 years and 6 months, previously identified as late talkers (LT), compared to typically developing (TD) peers in naturalistic child–adult conversations. Data from the CHILDES Clinical English Ellis Weismer Corpus included 36 LT and 37 TD children. Verbal backchannels were analysed for quantity, type diversity, temporal distribution, and responses to opportunity points. TD children produced more verbal backchannels per minute of adult speech, especially in the middle and final conversation stages. While both groups preferred simple forms, TD children exhibited greater functional flexibility and entropy. LT children responded to fewer opportunity points, with reduced overlap and more missed chances. Despite age-appropriate standardised scores, LT children displayed persistent pragmatic deficits. These findings highlight assessing conversational skills in natural contexts and the need for targeted interventions to enhance socially coordinated language use in 5-year-old children with a late-talking history.

Vocabulary development is essential to early language acquisition, supporting cognitive, social, and academic growth. While much research focuses on general vocabulary, studies on multiple-meaning words – polysemous (related meanings) or homonymous (unrelated meanings) – are limited. This study focused on the expressive lexicon, examining (1) the progression of multiple-meaning word acquisition across ages 3, 4, and 5; (2) differences in acquisition between polysemous and homonymous words; and (3) the impact of a gamified intervention program on multiple-meaning word knowledge. Results showed age-related gains in multiple-meaning word knowledge, from ages 3 to 5. Polysemous words showed a trend of improvement from age 3, whereas homonymous word gains emerged only from age 4. The intervention program enhanced retrieval across all ages, with greater benefits for ages 4 and 5. These findings deepen understanding of expressive multiple-meaning vocabulary development in preschoolers and highlight age-related and semantic-category differences.

Efficient language screening methods are needed for older school-age children and adolescents with suspected subclinical English language weaknesses. Twenty-five English-speaking monolingual children and fourteen Spanish-English bilingual children between the ages of 9;0 and 12;9 completed a nonword repetition task, a sentence repetition task, two grammaticality judgement tasks, and a passage comprehension task were examined relative to standard scores on the Clinical Evaluation of Language Fundamentals-4. When stepwise regression analyses were performed to evaluate the utility of each measure to predict our language outcome measure, the optimal model for monolingual children consisted only of the sentence repetition task. For the group of bilingual children, the optimal model consisted of the sentence repetition task and the passage comprehension task. These results provide support for the use of sentence repetition to gain insight into the English language proficiency of school-age children and adolescents with possible subclinical English language weaknesses.

This study investigates code-switching (CS) within the noun phrase in Portuguese–German bilingual children and adolescents (aged 8–16) in German-speaking Switzerland. Using an elicited imitation task with 49 participants, we examine how linguistic and extralinguistic factors shape CS behaviour. The experiment manipulated matrix language (German vs. Portuguese), insertion type (adjective vs. noun), and adjective position (prenominal vs. postnominal). The results show that CS strategies vary depending on the grammatical properties of the matrix language. In German, prenominal adjective position—regardless of the language of the inserted adjective—was the strongest predictor of repetition accuracy. In Portuguese, the language of the adjective played a central role. We propose the Constraint Integration Model to account for the interaction between matrix-language properties and lexical features. Additionally, older age and more positive attitudes towards German increased the likelihood of producing switched utterances.

Researchers have investigated later language development for more than 80 years. As a result, a great deal of information has been learned about the nature and substance of language development beyond the preschool years. This article highlights topics that were studied each decade, beginning with the 1940s and continuing to the present. Understanding the history of research in this area is essential for current investigators who seek to contribute new information to the discipline and for clinicians and teachers who seek to apply the information that has already been learned in their daily work with school-age children, adolescents, or young adults.

This study examines cross-linguistic influence (CLI) in the production of wh-questions by child heritage speakers of Mandarin aged 6;9 to 16;2 years in Canada. The form of CLI addressed is wh-fronting in Mandarin object-questions (where fronting is ungrammatical) and when-questions (where fronting is dispreferred). Our goals were, first, to determine whether the children front more frequently relative to their mothers; and second, to determine the impact of structural overlap between languages (operationalized by question type), relative language dominance, and age on the rate of children’s fronting. Results show that the children front more frequently, and in more contexts, than do their mothers, indicating CLI. Structural overlap increased the likelihood of fronting for only some children, whereas greater dominance in English increased the likelihood of fronting for the group. Age did not correlate with changes in rates of fronting, indicating that CLI may sometimes reflect permanent divergence from the parental grammar.

This study is concerned with Albanian children speaking a nonstandard dialect who learn Standard Albanian (SA) in primary school. Our main research question is whether the phonetic characteristics of these children’s first dialect are influenced by their learning of SA. We followed longitudinally 48 children in 1st, 2nd, and 5th grades (24 girls, 24 boys, 6–11 years old), some of whom grew up in a village, the others in a city. A picture-naming task was used to record four vowel features of interest, which were analyzed acoustically, then statistically with distributional regression models and generalized additive models. We found evidence that the children’s first dialect was affected by SA, suggesting that by 5th grade, they were not fully proficient at distinguishing between the two systems. The four analyzed features followed different developmental trajectories, similar to adults acquiring a second dialect, and similar to feature selectivity observed in language change.

This study investigates the impact of socio-economic status (SES) on children’s vocabulary, focusing on the distinction between vocabulary breadth (number of words known) and vocabulary depth (quality of word knowledge). It aims to determine whether SES affects both dimensions equally and whether the relationship between SES and vocabulary depth is mediated by vocabulary breadth. Participants were 219 children schooled in France in fourth and fifth grades who had French as their dominant language. Analyses showed that SES significantly influences vocabulary breadth, as predicted by previous research. Importantly, it also impacts vocabulary depth. Mediation analysis revealed that vocabulary breadth can mediate this effect depending on the task used to measure vocabulary depth.

In Mandarin Chinese, numeral classifiers form a grammatical category that is syntactically obligatory when a noun is modified by a numeral or a demonstrative. The appropriate choice of a classifier is associated with the semantic properties of its corresponding noun and is context dependent. Experience with language is needed to learn these patterns, but little is known about how classifiers are structured in children’s language environments. We compared the frequency and distribution of classifier phrases in four corpora: child-directed speech, children’s television shows, children’s books, and adult-directed speech. Classifier usage in children’s books was more diverse than in both child-directed and adult speech. Books contained more specific classifiers that co-occurred with a higher proportion of unique nouns, whereas everyday speech relied on more generic classifiers. Books therefore provide access to classifier–noun combinations that are rare in speech. Implications for language development and language processing are discussed.

Understanding verbal irony involves detecting that the speaker’s intended meaning contrasts with the literal meaning. This is challenging for children as the underlying skills required to understand irony may not be fully developed. We investigated how 10-year-olds’ working memory, empathy skills, and gender were related to their processing and comprehension of written irony. Data from two previous eye-tracking experiments with 97 children (46 girls and 51 boys) were analysed. Results showed that children with stronger empathy skills had higher irony comprehension accuracy and were less likely to reread ironic phrases. Higher working memory was linked to faster processing of irony but did not lead to higher comprehension. Conversely, lower working memory was associated with more accurate irony comprehension. Child gender was not related to irony comprehension. These results imply that working memory and emotional perspective-taking are important for children’s irony comprehension, underscoring theories that take individual differences into account.

This study examines the interaction between regularity and complexity in the acquisition of morphology and morpho-syntax in Hebrew nominal inflection. Seventy-eight Hebrew-speaking children, ages 4–8, were tested, using sentence completion tasks, on nine structures from three linguistic systems: singular adjectival agreement, noun pluralization, and plural adjectival agreement. Regularity and complexity emerged as organizing factors across ages: regular structures precede irregular ones, and within each level of regularity, less complex structures were acquired before more complex ones. The findings are discussed within the Dual-Route Model pointing to the difference between rule-governed and memory-based knowledge, while suggesting that the advantage of regularity could be attributed to frequency as well as to the strength of regularity cues in language acquisition, as proposed by Usage-Based models. The advantage of less complex structures over more complex ones is accounted for by the greater cognitive and linguistic effort required to acquire the latter.

The present study examined whether mothers’ pointing and the interaction between maternal pointing and infants’ point-following performance predict infants’ receptive and expressive vocabulary. At each month from 8 to 12, Turkish-speaking mother–infant dyads (N = 56) participated in the decorated room paradigm to determine pointing frequency and the point-following paradigm to determine whether infants follow points to surrounding pictures. Receptive and expressive vocabulary was measured at 14 and 18 months, respectively, using the Turkish CDI. Infants’ point-following performance at 11 months predicted their receptive vocabulary. Moreover, the interaction between maternal pointing and infant point-following at 12 months predicted receptive vocabulary, indicating that maternal pointing frequency predicted infants’ receptive vocabulary only for advanced point-followers, not for visual-field point-followers. We found no significant association between maternal pointing or infants’ point-following performance with expressive vocabulary. These findings suggest that infants’ point-following performance plays a role in their early word learning during mother–infant interactions.

This study tested the hypothesis that caregiver scaffolding and child engagement are tightly coupled during shared book reading’s word-learning moments. It also examined whether this coupling is consistent or variable across print and digital reading media. Word-learning episodes were coded from a corpus of videorecorded shared-reading interactions between caregiver–child dyads (N = 78, children’s age range = 4;0–5;11). Results support the prediction that scaffolding and engagement are coupled during word-learning moments. This coupling was robust across reading media. Further, child age was a significant predictor of engagement. These findings confirm that engagement is a critical social interaction mechanism involved in the scaffolding process that supports word learning.

In the extant literature on the development of the SES-related vocabulary gap, effects of low-income status and immigrant background often overlap. This study compared vocabulary trajectories in Italian (societal language) with normative data and investigated environmental factors related to vocabulary development in 83 toddlers (49% girls) from equivalent lowincome monolingual (28) and bilingual immigrant (55) families, from 18 to 36 months. Childcare teachers assessed vocabulary every 6 months using the Italian MacArthur–Bates Communicative Development Inventory (CDI). Parents reported information about environmental factors. Results based on a simulation approach showed that, at each assessment time, the participants’ median vocabulary scores were lower than normative data from the CDI. Mixed models considering environmental factors revealed that bilinguals’ vocabulary in Italian was lower than monolinguals’ from 18 to 30 but not at 36 months. In both groups, maternal education and home language activities positively predicted vocabulary from 18 to 36 months.

This study aims to examine the role of early signing input on the robust reliance on ASL basic word order by deaf adult ASL signers who are exposed to different types of signing (ASL versus signing systems, SS) by early childhood. We used a sentence-picture matching task involving transitive ASL sentences in subject–verb–object order with consistent or conflicting animacy cues. All signers with early ASL input (12 native signers, 12 non-native signers with early ASL) showed robust reliance on ASL word order and good bilingual skills, while 37.5% (6/16) non-native signers with early exposure to SS showed a weak representation of ASL basic word order along with lower bilingual proficiency. These results suggest that the critical period effects for syntactic development are not limited to severe deprivation but can also manifest when early language is insufficient. Early, rich, and consistent language input during early childhood is required for syntactic development.

Adults exhibit different acoustic characteristics in infant-directed speech (IDS) compared to adult-directed speech (ADS). We investigate differences in voice quality between IDS and ADS in sentences read aloud by Hungarian mothers, using longitudinal data gathered at various child ages (4, 8, 18 months). Vowels in IDS are found to be breathier than those in ADS, regardless of the infant’s age. Possible motivations for this difference may include emotional expressions, as breathiness relates to positive emotions, and speech entrainment, since the speech of children is breathier than that of adults.

The connection between working memory (WM) and the breadth of vocabulary knowledge (BVK) in foreign language young learners remains underexplored, particularly with respect to how these constructs co-develop across the primary school years. Although growth in WM has been linked to early gains in BVK, the directionality and temporal dynamics of their association are not well understood. Utilizing a cross-lagged panel design, this study tracked the development of WM and BVK in 158 young learners from grade 1 to grade 5. Results unveiled lagged associations between WM and BVK, suggesting that working memory serves as a valuable indicator for future BVK acquisition, while also indicating that accumulated BVK may, in turn, exert an influence on WM. These findings highlight a complex, bi-directional relationship between WM and BVK throughout primary school students’ formative years, in line with the transactional model.

This study investigates the development of canonical proportion (CP), an indicator of speech development, across diverse language and environmental contexts. Using the Speech Maturity Dataset (SMD) comprising 366 children, aged 0;2–6;4, across 10 different languages and cultures, we explore the influence of multilingual exposure, language syllable complexity, and community type (industrialised, non-industrialised) on CP. We find that monolingual children display higher CP measures than their multilingual peers. In addition, CP is higher for children learning languages with simple syllable complexity than those with more complex syllables. We also find no significant differences in the CP trajectory of children from industrialised versus non-industrialised communities. Integrating these findings in the broader literature, we highlight the importance of diversifying participant samples to capture the complex relationship between language exposure, social environment, and language development.