Previous research indicates that strong right-hand preference predicts performance in other skills, such as vocabulary size and executive function (EF). The purpose of this study was to assess the relationship between these functions, as well as social competence (SC), in a sample of preschool children. We used parent questionnaires and/or tabletop assessments to measure hand preference, fine motor skills, language, EF, and SC in 81 three- to five-year-old children. The results strengthened the evidence of a connection between right-hand use for pointing and vocabulary performance but indicated that right-hand use was not related to EF or SC. Further, the findings revealed a reciprocal connection between vocabulary and SC as well as EF and SC, but not vocabulary and EF. We discuss the implications of these connections for early childhood development.

Expanded vowel or tone space in IDS has traditionally been interpreted as evidence of enhanced acoustic contrasts. However, emerging evidence from various languages shows that the within-category acoustic variability of vowels and tones also increases in IDS, offsetting the benefit of space expansion and leading to non-enhanced, or reduced acoustic contrasts. This study re-analysed a corpus of Mandarin IDS and ADS, showing that, relative to ADS, vowels and tones in IDS display greater variability, resulting in non-enhanced contrasts. Thus, given increased variability, expanded vowel or tonal space in IDS may not necessarily equate to enhanced acoustic contrasts.

The main aim of this study, which presents the Slovenian adaptation of the Macarthur-Bates Communicative Development Inventory CDI–III, was to investigate the characteristics of language development in monolingual Slovenian-speaking children aged 30–48 months. In addition, we examined the relationships between different measures of child language assessed by the CDI–III, namely vocabulary, grammar and metalanguage. The sample comprised 301 children whose language was assessed by their parents using the Slovenian version of the CDI–III. The results indicate that language development at this age continues to progress relatively quickly, particularly in terms of children’s metalinguistic abilities, although there are large individual differences in language ability between children of the same age. The findings also indicate that some of the pre-existing relationships established between the different domains of infant and toddler language ability persist into early childhood, with vocabulary emerging as an important predictor of children’s grammar.

How do children learn the language-to-concept mappings within the domain of Mechanical Support – a spatial domain involving varied and complex force-dynamic relations between objects based on specific mechanisms (stickiness, clips, etc.)? We explore how four- and six-year-olds, and adults encode dynamic events and static configurations of Mechanical Support via attachment (picture put on a door). Participants viewed spatial configurations (Experiment 1 – in dynamic events or Experiment 2 – in static states) and were then prompted with the question, “Can you tell me what my sister did with my toy?” Children and adults used lexical verbs, and the visibility of the mechanism influenced the type of verb used. Also, whereas children preferentially used Orientation Verbs (e.g., “hang”), adults preferentially used Verbs of Attaching (e.g., “tape,” “stick”). Our findings shed light on how children acquire mechanical support language and the linguistic and cognitive constraints involved.

This study investigates how phonological competition affects real-time spoken word recognition in deaf and hard of hearing (DHH) preschoolers compared to peers with hearing in the normal range (NH). Three-to-six-year olds (27 with NH, 18 DHH, including uni- and bilateral hearing losses) were instructed to look at pictures that corresponded to words alongside a phonological competitor (e.g., /bin-pin/) vs. an unrelated distractor (e.g., /toy-bed/). Phonological competitors contrasted in either voicing or place of articulation (PoA), in the onset or coda of the word. Relative to peers with NH, DHH preschoolers showed reduced looks to target in reaction to the spoken words specifically when competition was present. DHH preschoolers may thus, as a group, experience increased phonological competition during word recognition. There was no evidence that phonological properties (voicing vs. PoA, or onset vs. coda) differentially impacted word recognition.

Children’s speech becomes longer and more complex as they develop, but the reasons for this have been insufficiently studied. This study examines how changing linguistic choices in children are linked to interactive factors by analysing Who-question sequences in Japanese child–caregiver conversations. The interactive factors in focus are progressivity and balanced joint activity, which are core aspects of conversational interaction. Our analysis reveals that as children respond to Who-questions, their responses grow in length and multifunctionality. This growth is positively associated with progressivity, namely a quicker completion of the question sequence, and reduced functional load in the interlocutor’s contributions, resulting in more balanced joint activity. These findings suggest that children adapt their linguistic choices by observing and aligning them with their interactive goals in conversational sequences.

Children’s acquisition of variation in the target language depends on a number of factors not yet well understood. This study probes the acquisition of morphological variation in two unrelated languages, Croatian (Slavic) and Estonian (Finnic), focussing on parallel forms of a lexeme expressing a single grammatical category (a phenomenon known as morphological overabundance). We conducted a cross-linguistic elicitation experiment with 140 monolingual, typically developing children aged 3;0 to 6;11 (80 learning Croatian, 60 Estonian). We elicited genitive plural forms in Croatian and partitive plural in Estonian, with lexemes which either are invariant or allow more than one form. Children in both languages were less accurate with lexemes with parallel forms, indicating that the morphological variation hindered acquisition. Pattern type frequency was found to affect accuracy in both languages. Children’s choice between two parallel forms was unaffected by age, but significant language-specific differences emerged.

This study evaluates how language exposure and mothers’ language dominance relate to infants’ early bilingual vocabulary development in a low-socioeconomic status (SES) sample from an understudied population: Mexican Indigenous bilinguals. Thirty-two mother–child dyads participated. All mothers were bilingual speakers of Spanish and one of Mexican Indigenous languages, including Zapotec, Mixtec, and Otomi. Infants’ (between 16 and 37 months) vocabulary size was estimated in both languages using the Mexican Spanish version of the MacArthur-Bates CDI II. Infants’ language exposure, mothers’ bilingual profile, and their SES were estimated on numerical scales. The results of Spearman correlations showed infants’ vocabulary size in Spanish grows with age, while their vocabulary in the Indigenous language depends on relative language exposure. Mothers’ language dominance correlated with Indigenous language exposure and infants’ vocabulary size in the Indigenous language. These findings are discussed in the context of early bilingual vocabulary acquisition in speakers of minority languages.

Irony comprehension requires going beyond literal meaning of words and is challenging for children. In this pre-registered study, we investigated how teaching metapragmatic knowledge in classrooms impacts written irony comprehension in 10-year-old Finnish-speaking children (n = 41, 21 girls) compared to a control group (n = 34, 13 girls). At pre-test, children read ironic and literal sentences embedded in stories while their eye movements were recorded. Next, the training group was taught about irony, and the control group was taught about reading comprehension. At post-test, the reading task and eye-tracking were repeated. Irony comprehension improved after metapragmatic training on irony, suggesting that metapragmatic knowledge serves an important role in irony development. However, the eye movement data suggested that training did not change the strategy children used to resolve the ironic meaning. The results highlight the potential of metapragmatic training and have implications for theories of irony comprehension.

Despite the importance of cognitive development for vocabulary acquisition, limited attention has been given to the impacts of cognitive factors on this phenomenon from a longitudinal perspective. This study evaluates the longitudinal development of such factors (i.e. metacognitive knowledge, working memory, and non-verbal intelligence) and L2 vocabulary knowledge growth in 210 young second language learners enrolled in a bilingual programme in China. Results supported individual differences in the initial level and the growth rate of learners’ cognitive development and vocabulary knowledge growth: a higher starting level of cognitive development correlated with a higher level of vocabulary knowledge and a faster rate of vocabulary knowledge growth. Findings revealed particularly significant predictive role of metacognitive knowledge on vocabulary knowledge, followed by non-verbal intelligence and working memory. Relevant implications were discussed based on the findings.

Numerous developmental findings suggest that infants and toddlers engage predictive processing during language comprehension. However, a significant limitation of this research is that associative (bottom-up) and predictive (top-down) explanations are not readily differentiated. Following adult studies that varied predictiveness relative to semantic-relatedness to differentiate associative vs. predictive processes, the present study used eye-tracking to begin to disentangle the contributions of bottom-up and top-down mechanisms to infants’ real-time language processing. Replicating prior results, infants (14-19 months old) use successive semantically-related words across sentences (e.g., eat, yum, mouth) to predict upcoming nouns (e.g., cookie). However, we also provide evidence that using successive semantically-related words to predict is distinct from the bottom-up activation of the word itself. In a second experiment, we investigate the potential effects of repetition on the findings. This work is the first to reveal that infant language comprehension is affected by both associative and predictive processes.

We explored whether bilingual toddlers make use of semantic and phonological overlap between their languages to learn new words. We analysed cross-sectional and longitudinal CDI data on the words understood and produced by 1.0 to 3.0-year-old bilingual toddlers with English and one additional language. Cognates were more likely to be understood and produced compared to non-cognates. Cognate effects were modulated by whether the toddler knew the translation equivalent in the other language, highlighting that young learners are sensitive to the similarities across their languages. Additionally, exploratory analyses suggest that children with smaller vocabularies rely more on translation equivalents to support the acquisition of difficult words. Children with larger vocabulary sizes exhibited no preference for translation equivalents in comprehension, and a preference for new concepts in production. The rapid acceleration of vocabulary growth in the second year of life may explain this developmental change in translation equivalent preference.

Words said aloud are typically recalled more than words studied under other techniques. In certain circumstances, production does not lead to this memory advantage. We investigated the nature of this effect by varying the task during learning. Children aged five to six years were trained on novel words which required no action (Heard) compared to Verbal-Speech (production), Non-Verbal-Speech (stick out tongue), and Non-Verbal-Non-Speech (touch nose). Eye-tracking showed successful learning of novel words in all training conditions, but no differences between conditions. Both non-verbal tasks disrupted recall, demonstrating that encoding can be disrupted when children perform different types of concurrent actions.

Using the syntactic priming paradigm, this study investigated abstract syntactic knowledge of Chinese transitive structures (i.e., subject-verb-object [SVO], BA, and BEI) in deaf children with cochlear implants (CIs). Specifically, we focused on the differences in the development of various syntactic structures (within CI children and compared with their typically hearing children) and the possible individual differences during this process. Results showed that both CI and hearing children exhibited structural priming for all syntactic structures (i.e., SVO, SbaOV structure [agent-patient ordering], and ObeiSV structure [patient-agent ordering]) after comprehending and repeating the prime sentence regardless of verb repetition. However, verb repetition induced an intense abstract priming effect in CI children but not hearing children, with the lexical boost effect more significant for SVO and BA structures. In addition, CI children’s working memory capability modulated the production of the BA structure but not SVO and BEI structures.

Although family factors are considered important for children’s language acquisition, the evidence comes primarily from affluent societies. Thus, this study aimed to examine the relations between family factors (family’s socioeconomic status [SES], home literacy activities, access to print resources, and parental beliefs) and children’s vocabulary knowledge in both urban and rural settings in China. Data from 366 children (urban group: 109, 4.85 years; rural group: 257, 4.89 years) were collected. Results showed that whereas family’s SES significantly predicted access to print resources and children’s vocabulary knowledge in the rural group, parental beliefs directly predicted children’s vocabulary knowledge in the urban group. Multigroup analysis showed that the associations of family’s SES and access to print resources with children’s vocabulary knowledge were stronger in the rural group than in the urban group. Our findings highlight the importance of considering contextual settings when conceptualising the role of family factors in children’s language acquisition.

This study is one of the few research efforts investigating unexpected non-interactive foreign language acquisition in children with Autism Spectrum Disorder (ASD). Participants included 46 English-Hebrew-speaking children (ages 4;10 to 12;0): 14 autistic children who acquired English via non-interactive input (ASD-NI); 12 autistic children (ASD-Nat), and 20 non-autistic children with typical language development (TLD-Nat) who acquired English and Hebrew naturalistically. Morpho-syntactic abilities were assessed using Sentence Repetition tasks in both languages. The results showed no group differences for morpho-syntax in English; in Hebrew, the ASD-NI group scored similarly to the ASD-Nat group but lower than the TLD-Nat group. Individual performance differences between Hebrew and English were observed across all groups. Additionally, correlations between exposure and SRep scores were found in both groups for Hebrew but not English. These findings highlight diverse paths to language acquisition in ASD, with children acquiring foreign languages via both naturalistic and non-interactive input.

In this longitudinal study, we compare the age of reaching early developmental milestones in bilingual and monolingual children and between the bilinguals’ two languages. We present data from 302 Polish bilinguals (living outside of Poland with various majority languages) and 302 Polish monolinguals, aged M = 12.78 months on study entry (range: 0–24 months), matched on sex, age at study entry, duration of parental reporting, and parental education. The milestones under investigation include crawling, walking, babbling, first, 10th, 50th word, and first multi-word utterances. The data was collected with a specially designed mobile app, in which parents reported their children’s development repeatedly. Using this relatively big sample and looking at a wide range of investigated milestones, we present evidence that typical bilingual development follows a trajectory similar to monolingual development. We also evaluate the feasibility and usefulness of online data collection using mobile apps to study early language development.

It is important to assess learning in both familiar and unfamiliar conditions to determine the extent of learning generalisation. In this study, we evaluated parent language outcomes of LENA Start™, a parent-implemented intervention, using distal measures derived from a parent–child free play interaction.

Forty-four parents and their child (mean: 20.8 months) participated in LENA Start™ or early childhood education curriculum intervention, in either English (n = 34) or Spanish (n = 10). We completed between- and within-group analyses using language and communication behaviour measures derived from parent–child interactions elicited outside the home with researcher-supplied materials (i.e., distal measures).

Group comparisons revealed significant differences on a subset of behavioural measures. Spanish-speaking parents in the LENA Start™ group demonstrated significant gains on three measures. While LENA Start™ has been associated with parent gains on proximal language measures, the results of this study reveal limited generalisation of skills based on distal measures.

We investigated the dynamics of communicative initiation in infant−caregiver interactions across ages and language abilities. Analyses of 228 Language ENvironment Analysis (LENA) recordings from 141 Korean adult−child dyads (60 girls; aged 7−30 months) replicated the initiator effect reported in North American populations. This effect, demonstrated by longer utterances, more frequent speech, and shorter response times in self-initiated interactions for both children and adults, suggests potential cross-cultural consistency in this conversational dynamic and remained consistent across ages in most conversational measures. A focused analysis of 13–14 month-olds (N = 40) and their K-CDI scores revealed that the initiator effect in segment duration and number persisted across most vocabulary percentiles. Additionally, nuanced findings indicated that caregivers increased their input frequency and adjusted segment duration in adult-initiated conversations in tandem with children’s higher receptive abilities. The robustness of the initiator role across cultures, ages, and vocabulary abilities points to a fundamental aspect of human communication.

This study will investigate how children acquire the option to drop the subject of a sentence, or null subjects (e.g., “Tickles me” instead of “He tickles me”). In languages that do not permit null subjects, children produce sentences with null subjects from 1 to 3 years of age. This non-adultlike production has been explained by two main accounts: first, the null subject sentences may accurately reflect the children’s linguistic knowledge, that is, a competence account. Alternatively, they may result from immature processing resources, therefore underestimating children’s competence, that is, a performance account. We will test the predictions of these accounts by using a central fixation preference procedure and elicited imitation to measure children’s comprehension and production, respectively, in monolingual 19- to 28-month-olds acquiring English (a non-null subject language) and Italian (a null subject language). The results will shed light on acquisition across languages, and the features that provide evidence to a learner.