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.

Speakers consider their listeners and adjust the way they communicate. One well-studied example is the register of infant-directed speech (IDS), which differs acoustically from speech directed to adults. However, little work has explored how parents adjust speech to infants across different contexts. This is important because infants and parents engage in many activities throughout each day. The current study tests whether the properties of IDS in English vary across three in-lab tasks (sorting objects, free play, and storytelling). We analysed acoustic features associated with prosody, including mean fundamental frequency (F0, perceived as pitch), F0 range, and word rate. We found that both parents’ pitch ranges and word rates varied depending on the task in IDS. The storytelling task stood out among the tasks for having a wider pitch range and faster word rate. The results depict how context can drive parents’ speech adjustments to infants.

English-speaking children sometimes make errors in production and comprehension of biclausal questions, known as “Scope-Marking Errors”. In production, these errors surface as medial wh questions (e.g., What do you think who the cat chased? (Thornton, 1990)). In comprehension, children respond to questions like How did the boy say what he caught? by answering what was caught (de Villiers & Roeper, 1995). These errors resemble wh-scope marking questions, attested in languages like German. Together, these errors suggest temporary adoption of multiple UG-licensed grammars (e.g., Yang, 2002). However, Lutken et al. (2020) found that children who make these errors in production do not necessarily make errors in comprehension and vice versa. They suggest these errors stem from children’s immature processing mechanisms. This article examines children’s production, comprehension, and processing capabilities, specifically working memory (WM). We find a correlation between WM and error rate and suggest separate causes for production and comprehension errors.

A growing body of research has found that talking to young children is positively associated with language outcomes. However, there is tremendous heterogeneity in the design of these studies, which could potentially affect the strength and reliability of this association. The present meta-analysis, comprising 4760 participants across 71 studies, goes beyond prior research by including: 1) more recent studies, 2) non-English-speaking populations, 3) more fine-grained categorization of measures of input, 4) additional moderators, and 5) a multilevel model design allowing us to consider multiple effect sizes per study. We find a moderate association between input and outcomes (R2=0.04-0.07) across four input measures, with some evidence of publication bias. We find no differences in effect size across any of the input measures. Child age and study duration moderated some effects of input. Our findings suggest that language input-outcome associations remain robust but modest across a multitude of contexts and measures.

By comparing infant-directed speech to spouse- and dog-directed talk, we aimed to investigate how pitch and utterance length are modulated by speakers considering the speech context and the partner’s expected needs and capabilities. We found that mean pitch was modulated in line with the partner’s attentional needs, while pitch range and utterance length were modulated according to the partner’s expected linguistic competence. In a situation with a nursery rhyme, speakers used the highest pitch and widest pitch range with all partners suggesting that infant-directed context greatly influences these acoustic features. Recent findings showed that these speakers expressed more intense positive emotions towards their infants and spouses than towards their dogs. Our results revealed different patterns, leading us to conclude that these acoustic features are not simple by-products of emotional speech. Instead, they are dynamically and functionally used in accordance with the speech context and the audience’s expected needs and capabilities.

To investigate how a high risk for infant neurological impairment affects the quality of infant verbal interactions, and in particular properties of infant-directed speech, spontaneous interactions between 14 mothers and their 4.5-month-old infants at high risk for neurological disorders (7 female) were recorded and acoustically compared with those of 14 dyads with typically developing infants (8 female). Mothers of at-risk infants had proportionally less voicing, and the proportion of voicing decreased with increasing severity of the infants’ long-term outcome. Follow-up analysis based on manual annotation of phonation style revealed breathy phonation as more common toward infants with more severe long-term outcomes (N=7; 44.7% of speech) than controls (N=14; 22.0%; p=0.005) or at-risk infants with typical or mildly abnormal long-term outcomes (N=7; 16.5%; p=0.002). The results indicate that maternal phonation style during early dyadic interactions is affected by the infant’s neurological condition.

The Arabic development of Syrian refugee children (N = 133; mean age = 9;4 at Time 1) was examined over 3 time periods during their first five years in Canada. Children were administered sentence repetition and receptive vocabulary tasks in English and Arabic, and information about age-of-arrival (AOA), schooling in Arabic and language environment factors was obtained via parent report. Older AOA was associated with superior Arabic abilities across time, but regardless of AOA, children showed plateau/attrition patterns in Arabic and shifts to English dominance by Time 3. Increases in English over Arabic were observed for language use at home and language-rich activities overtime. Stronger Arabic Time 3 outcomes were predicted by more Arabic and less English use with siblings, more schooling in Arabic, more frequent listening-speaking and extra-curricular activities in Arabic, and more Arabic use with friends. We conclude that the heritage language can be vulnerable even for first-generation bilinguals.

This study explored cognitive effects on narrative macrostructure in both languages of 38 Russian-German bilinguals aged 4;6 to 5;1‚ while controlling for demographic factors (sex, socioeconomic status) and language proficiency. Macrostructure was operationalised as story structure (SS) and story complexity (SC) using the Multilingual Assessment Instrument for Narratives. Nonverbal cognitive subtasks assessing shifting (Figure Ground), visual memory (Form Completion), and inhibition (Attention Divided) were administered. None of the cognitive skills influenced SS; however, they differentially impacted SC: Figure Ground affected Russian SC, while Form Completion affected German SC. Findings advance our understanding of how cognition affects oral narratives in bilingual preschoolers.

Children acquire vocabulary at different growth rates. The aim of this study was to identify subgroups of different vocabulary trajectories in a community sample of L1 German-speaking children aged 1;6 to 3;0 to enlarge the understanding of vocabulary trajectories. Parents filled out vocabulary checklists at four measurement times, each six months apart. Growth mixture modelling was used to naturally determine latent classes of observed vocabulary growth curve patterns. Six distinct trajectories of vocabulary growth were identified and characterised. Children’s (N=198) vocabulary abilities were divided into the following subgroups: “far above average” (2.0%), “above average” (6.6%), “typical” (70.2%), “below average” (14.1%), “early below average" but caught up with their peers over time (5.6%), and “far below average” (1.5%). Socioeconomic status differed significantly between subgroups.

The current study examined the relationship between interest, the home environment, and young Chinese children’s development of English as a second/foreign language in Hong Kong. Two hundred and seventy-four Hong Kong kindergartners were assessed on their interest in learning English and their English language skills (i.e., expressive and receptive vocabulary). Their parents completed questionnaires eliciting family socio-economic status, parental beliefs, and home learning environment. The results indicated that (1) interest was related to children’s English language abilities after controlling for children’s gender, non-verbal intelligence, and kindergarten type; (2) parents’ beliefs about their child’s English ability and self-efficacy were related to children’s interest in learning English; and (3) interest uniquely contributed to children’s English language ability in the home environment. The present findings provide evidence of the active role that children play in their second/foreign language development and highlight the significant influence of parental beliefs on children’s interest in learning English.

Infants’ language is often measured indirectly via parent reports, but mothers may underestimate or overestimate their infants’ word comprehension. The current study examined estimations of mothers from diverse educational backgrounds regarding their infants’ word comprehension and how these estimations are associated with their verbal input and infants’ receptive vocabulary at 14 months. We compared 34 infants’ looking-while-listening (LWL) performances with the mothers’ Turkish Communicative Development Inventory (TCDI) reports to calculate the mothers’ overestimation and underestimation. During free-play sessions, we assessed the mothers’ number of words, number of clauses, lexical diversity, and linguistic complexity. We found that mothers have overestimations and underestimations regardless of their educational background. Crucially, mothers’ only overestimations were positively associated with their number of words and lexical diversity. Mothers’ verbal input was not related to infants’ receptive vocabulary scores. The findings suggest that mothers’ input might be aligned with their estimations of their infants’ language capabilities, which might not reflect the infants’ true performance.

This study investigates Navajo verbs produced by four children, ages 4;07 to 11;02, during conversations with their caretakers. Analyses of 1600 verbs demonstrate that the bisyllabic verb form, consisting of a verb stem and a portion of the prefix string, is the most common pattern produced by the children. This indicates that Navajo-speaking children use meaningful units of verbal morphology that do not necessarily adhere to the linguistic boundaries normally ascribed to the Navajo verb complex. Further, the verbs are primarily intransitive and third-person singular constructions, which are minimally inflected. It is argued that these minimally-inflected verb forms are frequent not just because they are simpler, but also because they are highly productive as main verbs and are used to create phrasal verbs and nouns. These findings contribute to our general understanding of language development and to the growing body of research investigating children’s acquisition of endangered Indigenous languages.

This study investigates Mandarin-speaking children’s (age 3–7) comprehension development of novel and conventional metonymy, combining online and offline methods. Both online and offline data show significantly better performances from the oldest group (6-to-7-year-old) and a delayed acquisition of conventional metonymy compared with novel metonymy. However, part of offline data shows no significant difference between adjacent age groups, while the eye-tracking data show a chronological development from age 3–7. Furthermore, in offline tasks, the three-year-old group features a high choice randomness and the four-to-five-year-olds show the longest reaction time. Therefore, we argue that, not only age but also metonymy type can influence metonymy acquisition, and that a lack of socio-cultural experience can be a source of acquisition difficulty for children under six. Methodologically speaking, we believe that online methods should not be considered superior to offline ones as they investigate different aspects of implicit and explicit language comprehension.

Research shows that children’s home environment (e.g., the composition of their household and the resources available in it) has an impact on children’s language development. However, this research has mostly been conducted among English speakers from the minority world and has often only considered vocabulary size. This exploratory study investigated whether home environment factors are predictive of grammar development in Afrikaans-speaking (n = 117) and English-speaking (n = 102) toddlers in South Africa. Moreover, potential differences between these two language groups were explored. Results showed that home environment factors pertaining to family stability predicted two of the three grammar scores, namely total grammar and complex phrases. Cluster analysis showed distinct patterns of home environment factors between Afrikaans and English-speaking households, illustrating the importance of measuring these factors even across samples from the same country. This study shows that children’s home environment is an interconnected system and cautions against oversimplified single-factor approaches.

Private speech is a tool through which children self-regulate. The regulatory content of children’s overt private speech is associated with response to task difficulty and task performance. Parenting is proposed to play a role in the development of private speech as co-regulatory interactions become represented by the child as private speech to regulate thinking and behaviour. This study investigated the relationship between maternal parenting style and the spontaneous regulatory content of private speech in 3- to 5-year-old children (N = 70) during a problem-solving Duplo construction task. Sixty-six children used intelligible private speech which was coded according to its functional self-regulatory content (i.e., forethought, performance, and self-reflective). Mothers completed the Australian version of the Parenting Styles and Dimensions Questionnaire. Results revealed a significant positive association between maternal authoritative parenting and the frequency and proportion of children’s forethought type (i.e., planning and self-motivational) utterances during the construction task. There were no significant associations between maternal parenting style and other private speech content subtypes.

This study investigated the role of temperament in oral language development in over 200 Mandarin and Cantonese speakers in the Growing Up in New Zealand pre-birth longitudinal cohort study. Mothers assessed infant temperament at nine months using a five-factor Infant Behaviour Questionnaire-Revised Very Short Form. They also reported on children’s vocabulary and word combinations at age two using adapted MacArthur-Bates Communicative Development Inventory short forms. Regression analyses were employed to examine unique links between infant temperament and language, respectively, controlling for demographic factors. Fear was associated with larger English vocabularies for English-Mandarin speakers and larger Cantonese vocabularies for Cantonese speakers. Orienting capacity was associated with more advanced word combinations for Mandarin speakers, whereas negative emotionality was associated with less advanced word combinations for Cantonese speakers. Positive affect/surgency was associated with more advanced word combinations for English-Cantonese speakers. This study revealed predictive patterns of infant temperament across Chinese-speaking children’s multiple languages.