The ubiquity of frequency effects in first language acquisition

Frequency, redundancy, and context in bilingual acquisition

We report findings from a corpus-based investigation of three young children growing up in German-English bilingual environments (M = 3;0, Range = 2;3-3;11). Based on 2,146,179 single words and two-word combinations in naturalistic child speech (CS) and child-directed speech (CDS), we assessed the degree to which the frequency distribution of CDS predicted CS usage over time, and systematically identified CS that was over- or underrepresented in the corpus with respect to matched CDS baselines. Results showed that CDS explained 61% of the variance in CS single-word use and 19.3% of the variance in two-word combinations. Furthermore, the bilingual nature of the over or -underrepresented CS was partially attributable to factors beyond the corpus statistics, namely individual differences between children in their bilingual learning environment. In two out of the three children, overrepresented two-word combinations contained higher levels of syntactic slot redundancy than underrepresented CS. These results are discussed with respect to the role that redundancy plays in producing semiformulaic slot-and-frame patterns in CS.

The dynamics of multiword sequence extraction

Being able to process multiword sequences is central for both language comprehension and production. Numerous studies support this claim, but less is known about the way multiword sequences are acquired, and more specifically how associations between their constituents are established over time. Here we adapted the Hebb naming task into a Hebb lexical decision task to study the dynamics of multiword sequence extraction. Participants had to read letter strings presented on a computer screen and were required to classify them as words or pseudowords. Unknown to the participants, a triplet of words or pseudowords systematically appeared in the same order and random words or pseudowords were inserted between two repetitions of the triplet. We found that response times (RTs) for the unpredictable first position in the triplet decreased over repetitions (i.e., indicating the presence of a repetition effect) but more slowly and with a different dynamic compared with items appearing at the predictable second and third positions in the repeated triplet (i.e., showing a slightly different predictability effect). Implicit and explicit learning also varied as a function of the nature of the triplet (i.e., unrelated words, pseudowords, semantically related words, or idioms). Overall, these results provide new empirical evidence about the dynamics of multiword sequence extraction, and more generally about the role of statistical learning in language acquisition.

Frequent vs. infrequent words shape toddlers' real-time sentence comprehension

We examined how noun frequency and the typicality of surrounding linguistic context contribute to children's real-time comprehension. Monolingual English-learning toddlers viewed pairs of pictures while hearing sentences with typical or atypical sentence frames (Look at the… vs. Examine the…), followed by nouns that were higher- or lower-frequency labels for a referent (horse vs. pony). Toddlers showed no significant differences in comprehension of nouns in typical and atypical sentence frames. However, they were less accurate in recognizing lower-frequency nouns, particularly among toddlers with smaller vocabularies. We conclude that toddlers can recognize nouns in diverse sentence contexts, but their representations develop gradually.

Linking acoustic variability in the infants' input to their early word production

Exposure to talker variability shapes how learning unfolds in the lab, and occurs in the everyday speech infants hear in daily life. Here, we asked whether aspects of talker variability in speech input are also linked to the onset of word production. We further asked whether these effects were redundant with effects of speech register (i.e., whether speech input was adult- vs. child-directed). To do so, we first extracted a set of highly common nouns from a longitudinal corpus of home recordings from North-American English-learning infants. We then used the acoustic variability in how these tokens were said to predict when the children first produced these same nouns. We found that in addition to frequency, variability in how words sound in 6-17 month's input predicted when children first said these words. Furthermore, while the proportion of child-directed speech also predicted the month of first production, it did so alongside measurements of acoustic variability in children's real-world input. Together, these results add to a growing body of literature suggesting that variability in how words sound in the input is linked to learning both in the lab and in daily life. RESEARCH HIGHLIGHTS: Talker variability shapes learning in the lab and exists in everyday speech; we asked whether it predicts word learning in the real world. Acoustic measurements of early words in infants' input (and their frequency) predicted when infants first said those same words. Speech register also predicted when infants said words, alongside effects of talker variability. Our results provide a deeper understanding of how sources of variability inherent to children's input connect to their learning and development.

Contributions of Speaking, Listening, and Semantic Depth to Word Learning in Typical 3- and 4-Year-Olds

PURPOSE

This study examined learning via perception, learning via production, and semantic depth as contributors to word learning in preschool-aged children. There is broad evidence that semantic depth is an important contributor to word learning, especially when semantic cues are repeated and spaced out over time. Perceptual learning and production learning each support word learning sometimes, but not in all cases. The purpose of this study was to examine all three learning mechanisms within a single experimental paradigm.

METHOD

Thirty-six typically developing preschool children completed the experiment. They were familiarized with 16 novel words that were contextualized as alien names. These aliens came in four sets, each set comprising one base alien and three modified aliens marked by suffixes. Children completed four familiarizations: two in which they simply listened to the alien names (perceptual learning) and two where they repeated the alien names (production learning). Those conditions were crossed with a semantic depth manipulation (aliens with and without verbal semantic cues). Following each familiarization, referent identification and confrontation naming tasks were completed to assess learning.

RESULTS

Children were able to identify more alien referents following familiarizations with semantic depth. There were no significant effects of either perceptual learning or production learning.

CONCLUSIONS

This study confirms and expands on the benefits of semantic depth, but the results are unclear about the relative importance of perception and production to word learning. Nevertheless, the study suggests benefits to simultaneously studying multiple factors related to word learning.

Frequency and Universal Principles in the Acquisition of Word-Initial Consonant Clusters in Palestinian Arabic

PURPOSE

In this article, we present the results of our study on the acquisition of word-initial consonant clusters in Palestinian Arabic. The remarkable property of word-initial clusters in Palestinian Arabic is that they often violate the Sonority Sequencing Principle, a universal constraint that disfavors sonority fall (e.g., lba:n "gum") and, to a lesser degree, sonority plateau (e.g., kta:b "book"). Given the violation of the Sonority Sequencing Principle, the acquisition of word-initial consonant clusters serves as a fruitful ground for studying the interaction of universal principles and language-specific effects. The goal of the study was to shed light on the role of universal principles in language acquisition and how they interact with frequency.

METHOD

We carried out picture naming and sentence completion tasks with 60 monolingual and monodialectal children aged 2;00-5;00 (years;months), equally divided into six age groups. In addition, we built a small corpus of child-directed speech (CDS) to evaluate the distribution of the three sonority profiles of word-initial consonant clusters-rise, plateau, and fall.

RESULTS

We found a major language-specific effect in the cluster simplification strategies, with prothesis being the most common strategy (e.g., lbá:n → ilbá:n "gum"). However, this effect was not found in the youngest group (2;00-2;05), where the cross-linguistically favorite strategy of C-deletion was most common (e.g., lbá:n → bá:n "gum"). We also found a major effect of the Sonority Sequencing Principle in the children's productions, contrary to insignificant differences in CDS.

CONCLUSIONS

Our study supports the claim that language acquisition is affected by both language-specific effects and universal principles. As for the interaction of these factors, we show that the effect of universal principles emerges under two conditions: (a) in early speech (youngest age group), before children accumulate sufficient data that allow language-specific properties to override, and/or (b) when frequency does not play a role.

Children's acquisition of word order variation: A study of subject placement in embedded clauses in Norwegian

Norwegian embedded clauses give children two options for subject placement: preceding or following negation (S-Neg/Neg-S). In the adult language, S-Neg is the 'default' and highly frequent option, and Neg-S is infrequent in children's input. However, Neg-S may be argued to be the structurally less complex. We investigate whether children are aware of the existence of both subject positions, and if they prefer the more frequent or the less complex position. Through an elicited production task with monolingual Norwegian children (N=33, age 3;1-6;1) we find that children in general overuse the Neg-S option, and we suggest that children have an inherent preference for the less complex position, due to a principle of structural economy. We also find that a group of children display U-shaped development, first using only S-Neg, then only Neg-S and finally S-Neg again, and we relate this to structure building and economy of movement.

The acquisition of English modal constructions: a corpus-based analysis

The English modal system is complex, exhibiting many-to-one, and one-to-many, form-function mappings. Usage-based approaches emphasise the role of the input in acquisition but rarely address the impact of form-function mappings on acquisition. To test whether consistent form-function mappings facilitate acquisition, we analysed two dense mother-child corpora at age 3 and 4. We examined the influence on acquisition of input features including form-function mapping frequency and the number of functions a modal signifies, using innovative methodological controls for other aspects of the input (e.g., form frequency) and child characteristics (e.g., age as a proxy for socio-cognitive development). The children were more likely to produce the frequent modals and form-function mappings of their input but modals with fewer functions in caregiver speech did not promote acquisition of these forms. Our findings support usage-based approaches to language acquisition and demonstrate the importance of applying appropriate controls when investigating relationships between input and development.

Production of relative clauses in Cantonese-speaking children with and without Developmental Language Disorder

Developmental Language Disorder (DLD) has been explained as either a deficit deriving from an abstract representational deficit or as emerging from difficulties in acquiring and coordinating multiple interacting cues guiding learning. These competing explanations are often difficult to decide between when tested on European languages. This paper reports an experimental study of relative clause (RC) production in Cantonese-speaking children with and without DLD, which enabled us to test multiple developmental predictions derived from one prominent theory - emergentism. Children with DLD (N = 22; aged 6;6-9;7) were compared with age-matched typically-developing peers (N = 23) and language-matched, typically-developing children (N = 21; aged 4;7-7;6) on a sentence repetition task. Results showed that children's production across multiple RC types was influenced by structural frequency, general semantic complexity, and the linear order of constituents, with the DLD group performing worse than their age-matched and language-matched peers. The results are consistent with the emergentist explanation of DLD.

Infants who are rarely spoken to nevertheless understand many words

Theories of language development-informed largely by studies of Western, middleclass infants-have highlighted the language that caregivers direct to children as a key driver of language learning. However, some have argued that language development unfolds similarly across environmental contexts, including those in which childdirected language is scarce. This raises the possibility that children are able to learn from other sources of language in their environments, particularly the language directed to others in their environment. We explore this hypothesis with infants in an indigenous Tseltal-speaking community in Southern Mexico who are rarely spoken to, yet have the opportunity to overhear a great deal of other-directed language by virtue of being carried on their mothers' backs. Adapting a previously established gaze-tracking method for detecting early word knowledge to our field setting, we find that Tseltal infants exhibit implicit knowledge of common nouns (Exp. 1), analogous to their US peers who are frequently spoken to. Moreover, they exhibit comprehension of Tseltal honorific terms that are exclusively used to greet adults in the community (Exp. 2), representing language that could only have been learned through overhearing. In so doing, Tseltal infants demonstrate an ability to discriminate words with similar meanings and perceptually similar referents at an earlier age than has been shown among Western children. Together, these results suggest that for some infants, learning from overhearing may be an important path toward developing language.

Complementary food exposure and children's early understanding of food words: the approaching eating through language (APPEAL) study

Introduction

Language skills, such as the ability to understand words (receptive language), develop during infancy and are built through interactions with the environment, including eating. Exposure to complementary foods also begins in infancy and may play a significant role in language development, especially in understanding of food-related words. However, the relationship between the complementary foods to which a child is exposed and early language acquisition has not been previously studied. We hypothesized that young children's food-related receptive language (FRL) would reflect the complementary foods to which they were frequently offered by caregivers.

Methods

Caregivers of young children (4-26 months; n = 408) in the Approaching Eating through Language (APPEAL) Study in the US were surveyed via Qualtrics. FRL was assessed by caregiver-report via a modified MacArthur-Bates Communicative Development Inventory. Complementary foods offered (CFO) by caregivers were assessed using a modified Food Frequency Questionnaire. Latent Class Analysis (LCA) was implemented to identify, 1) groupings of foods frequently offered (>1x/week) and 2) groupings of food-related words understood by the young children.

Results

A 5-class best fit LCA model was identified for CFO (-log likelihood [-llik]=-8727) and for FRL (-llik=-5476). Cross-classification of the CFO and FRL derived classes revealed that children with higher exposure to complementary foods were perceived by caregivers to be most likely to also understand a greater number of food-related words (Probability=0.48). As expected, children having been offered a greater number of complementary foods and who understood a greater number of food-related words were older, compared to those with less complementary food exposure and food-related language acquisition (p < 0.001).

Discussion

These findings support the potential role of introduction to complementary foods in development of food-related language.

The different effects of a sensorimotor grounding on AoA between bilingual concepts

Introduction

Psycholinguistic studies have argued for the age of acquisition (AoA) of words as a marker of concept learning, showing that the semantic features of concepts themselves influence the age at which their labels are learned. However, empirical evidence suggests that semantic features such as imageability and linguistic phenomena such as frequency do not adequately predict AoA. The present study takes the developmental approach of embodied cognition and investigates the effects of sensorimotor experiences on the ease of acquisition of the concept acquired in bilinguals. Specifically, we investigated (1) whether the sensorimotor experience can explain AoA beyond frequency; (2) and whether these patterns are consistent across L1 Chinese and L2 English.

Methods

We conducted sensorimotor rating measures in both Chinese and English on 207 items in which Chinese-English bilingual adults were requested to evaluate the extent to which they experienced concepts by employing six perceptual senses and five effectors for actions located in various regions of the body. Meanwhile, data on AoA and frequency were collected.

Results

The present study showed the sensorimotor experience was closely linked with AoAs in both languages. However, the correlation analysis revealed a trend of higher correlations between AoAs for the same concepts and L1 Chinese, relative to L2 English for the present Chinese-English bilinguals. Importantly, the hierarchical regression analysis demonstrated that after controlling for frequency, sensorimotor experience explained additional variance in L1 AoA. However, L2 sensorimotor experience did not explain the variance in L2 AoA. Sensorimotor experience explained more share of variance in L1 AoA but frequency accounted for more variance in L2 AoA.

Discussion

The findings suggest that concept acquisition should consider the grounding in appropriate sensorimotor experience beyond linguistic phenomena like frequency.

Robustness of the random language model

The random language model [Phys. Rev. Lett. 122, 128301 (2019)0031-900710.1103/PhysRevLett.122.128301] is an ensemble of stochastic context-free grammars, quantifying the syntax of human and computer languages. The model suggests a simple picture of first-language learning as a type of annealing in the vast space of potential languages. In its simplest formulation, it implies a single continuous transition to grammatical syntax, at which the symmetry among potential words and categories is spontaneously broken. Here this picture is scrutinized by considering its robustness against extensions of the original model, and trajectories through parameter space different from those originally considered. It is shown here that (i) the scenario is robust to explicit symmetry breaking, an inevitable component of learning in the real world, and (ii) the transition to grammatical syntax can be encountered by fixing the deep (hidden) structure while varying the surface (observable) properties. It is also argued that the transition becomes a sharp thermodynamic transition in an idealized limit. Moreover, comparison with human data on the clustering coefficient of syntax networks suggests that the observed transition is equivalent to that normally experienced by children at age 24 months. The results are discussed in light of the theory of first-language acquisition in linguistics, and recent successes in machine learning.

A maturational frequency discrimination deficit may explain developmental language disorder

Auditory perceptual deficits are widely observed among children with developmental language disorder (DLD). Yet, the nature of these deficits and the extent to which they explain speech and language problems remain controversial. In this study, we hypothesize that disruption to the maturation of the basilar membrane may impede the optimization of the auditory pathway from brainstem to cortex, curtailing high-resolution frequency sensitivity and the efficient spectral decomposition and encoding of natural speech. A series of computational simulations involving deep convolutional neural networks that were trained to encode, recognize, and retrieve naturalistic speech are presented to demonstrate the strength of this account. These neural networks were built on top of biologically truthful inner ear models developed to model human cochlea function, which-in the key innovation of the present study-were scheduled to mature at different rates over time. Delaying cochlea maturation qualitatively replicated the linguistic behavior and neurophysiology of individuals with language learning difficulties in a number of ways, resulting in (a) delayed language acquisition profiles, (b) lower spoken word recognition accuracy, (c) word finding and retrieval difficulties, (d) "fuzzy" and intersecting speech encodings and signatures of immature neural optimization, and (e) emergent working memory and attentional deficits. These simulations illustrate many negative cascading effects that a primary maturational frequency discrimination deficit may have on early language development and generate precise and testable hypotheses for future research into the nature and cost of auditory processing deficits in children with language learning difficulties. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Wordform variability in infants' language environment and its effects on early word learning

Most research regarding early word learning in English tends to make the simplifying assumption that there exists a one-to-one mapping between concrete objects and their labels. In the current work, we provide evidence that runs counter to this assumption, aligning English with more morphologically-rich languages. We suggest that even in a morphologically-poor language like English, real world language input to infants does not provide tidy 1-to-1 mappings. Instead, infants encounter many variant wordforms for familiar nouns (e.g. dog∼doggy∼dogs). We explore this wordform variability in 44 English-learning infants' naturalistic environments using a longitudinal corpus of infant-available speech. We look at both the frequency and composition of wordform variability. We find two broad categories of variability: referent-changing alterations, where words were pluralized or compounded (e.g. coat∼raincoats); and wordplay, where words changed form without a notable change in referent (e.g. bird∼birdie). We further find that wordplay occurs with a limited number of lemmas that are usually early-learned, high-frequency, and shorter. When looking at all wordform variability, we find that individual words with higher levels of wordform variability are learned earlier than words with fewer wordforms, over and above the effect of frequency.

Preparing Student Clinicians to Provide Recast Therapy on Complement Clauses: A Training Program

PURPOSE

This study reports on a program to train student clinicians to provide recast therapy on complement clauses to children with developmental language disorder (DLD). To determine the efficacy of the program, we conducted secondary data analysis based on Owen Van Horne et al. (2023) and examined student clinicians' recasts after training and children's progress after treatment.

METHOD

Three student clinicians received a two-stage training, followed by a real intervention program targeting complement clauses in six children with DLD. A third of the intervention sessions were coded for the total number and number of unique verbs in complement clauses provided by the student clinicians. An elicited production task was completed to test children's knowledge of the target structure.

RESULTS

On average, student clinicians provided 30 targeted recasts to each child during each intervention session. They provided a greater number of and more variable input for that compared to WH complements. Children demonstrated significant improvement only in WH, but not in that, complements.

CONCLUSIONS

A targeted training program could strengthen clinicians' ability to provide recast therapy on complex syntax; however, future refinements should shorten and broaden training to include more targets. A mismatch between input patterns and learning patterns was observed. WH complement input is more stable than that input, given the less variable complement-taking verbs provided by the student clinicians and the overtness of the WH word as a stable complementizer, which may have facilitated the identification and extraction of the target syntactic structure.

Touchscreens can promote infant object-interlocutor reference switching

We re-examine whether the type of object played with influences parent-infant joint attention. A within-participants comparison of 24 parent-9-month-old dyads, used head-mounted eye-tracking to measure parental naming and infant attention during play with touchscreen apps on a touchscreen tablet or matched interactive toys. Infants engaged in sustained attention more to the toy than the tablet. Parents named objects less in toy play. Infants exhibited more gaze shifts between the object and their parent during tablet play. Contrasting previous studies, these findings suggest that joint tablet play can be more interactive than with toys, and raise questions about the recommendation that infants should not be exposed at all to such technology.

A changing role for transitional probabilities in word learning during the transition to toddlerhood?

Infants' sensitivity to transitional probabilities (TPs) supports language development by facilitating mapping high-TP (HTP) words to meaning, at least up to 18 months of age. Here we tested whether this HTP advantage holds as lexical development progresses, and infants become better at forming word-referent mappings. Two groups of 24-month-olds (N = 64 and all White, tested in the United States) first listened to Italian sentences containing HTP and low-TP (LTP) words. We then used HTP and LTP words, and sequences that violated these statistics, in a mapping task. Infants learned HTP and LTP words equally well. They also learned LTP violations as well as LTP words, but learned HTP words better than HTP violations. Thus, by 2 years of age sensitivity to TPs does not lead to an HTP advantage but rather to poor mapping of violations of HTP word forms. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The role of imageability in noun and verb acquisition in children with Down syndrome and their peers with typical development

Our main objective was to analyze the role of imageability in relation to the age of acquisition (AoA) of nouns and verbs in Spanish-speaking children with Down syndrome (DS) and their peers with typical development (TD). The AoA of nouns and verbs was determined using the MacArthur-Bates CDIs adapted to the profile of children with DS. The AoA was analyzed using a linear mixed-effect model, including factors of imageability, group, and word class, and controlling for word frequency and word length. This analysis showed that high imaginable and short words were acquired early. Children with DS acquired the words later than TD peers. An interaction between imageability and group indicated that the effect of imageability was greater in the DS group. We discuss this effect considering DS children's phonological memory difficulties. The overall results confirm the role that imageability and word length play in lexical acquisition, an effect that goes beyond word class.

Relative clause comprehension in Cantonese-speaking children with and without developmental language disorder

Developmental Language Disorder (DLD), present in 2 out of every 30 children, affects primarily oral language abilities and development in the absence of associated biomedical conditions. We report the first experimental study that examines relative clause (RC) comprehension accuracy and processing (via looking preference) in Cantonese-speaking children with and without DLD, testing the predictions from competing domain-specific versus domain-general theoretical accounts. We compared children with DLD (N = 22) with their age-matched typically-developing (TD) children (AM-TD, N = 23) aged 6;6-9;7 and language-matched (and younger) TD children (YTD, N = 21) aged 4;7-7;6, using a referent selection task. Within-subject factors were: RC type (subject-RCs (SRCs) versus object-RCs (ORCs); relativizer (classifier (CL) versus relative marker ge3 RCs). Accuracy measures and looking preference to the target were analyzed using generalized linear mixed effects models. Results indicated Cantonese children with DLD scored significantly lower than their AM-TD peers in accuracy and processed RCs significantly slower than AM-TDs, but did not differ from the YTDs on either measure. Overall, while the results revealed evidence of a SRC advantage in the accuracy data, there was no indication of additional difficulty associated with ORCs in the eye-tracking data. All children showed a processing advantage for the frequent CL relativizer over the less frequent ge3 relativizer. These findings pose challenges to domain-specific representational deficit accounts of DLD, which primarily explain the disorder as a syntactic deficit, and are better explained by domain-general accounts that explain acquisition and processing as emergent properties of multiple converging linguistic and non-linguistic processes.

Phonological acquisition depends on the timing of speech sounds: Deconvolution EEG modeling across the first five years

The late development of fast brain activity in infancy restricts initial processing abilities to slow information. Nevertheless, infants acquire the short-lived speech sounds of their native language during their first year of life. Here, we trace the early buildup of the infant phoneme inventory with naturalistic electroencephalogram. We apply the recent method of deconvolution modeling to capture the emergence of the feature-based phoneme representation that is known to govern speech processing in the mature brain. Our cross-sectional analysis uncovers a gradual developmental increase in neural responses to native phonemes. Critically, infants appear to acquire those phoneme features first that extend over longer time intervals-thus meeting infants' slow processing abilities. Shorter-lived phoneme features are added stepwise, with the shortest acquired last. Our study shows that the ontogenetic acceleration of electrophysiology shapes early language acquisition by determining the duration of the acquired units.

Explainability of neural networks for child language: Agent-First strategy in comprehension of Korean active transitive construction

This study investigates how neural networks address the properties of children's linguistic knowledge, with a focus on the Agent-First strategy in comprehension of an active transitive construction in Korean. We develop various neural-network models and measure their classification performance on the test stimuli used in a behavioural experiment involving scrambling and omission of sentential components at varying degrees. Results show that, despite some compatibility of these models' performance with the children's response patterns, their performance does not fully approximate the children's utilisation of this strategy, demonstrating by-model and by-condition asymmetries. This study's findings suggest that neural networks can utilise information about formal co-occurrences to access the intended message to a certain degree, but the outcome of this process may be substantially different from how a child (as a developing processor) engages in comprehension. This implies some limits of neural networks on revealing the developmental trajectories of child language. RESEARCH HIGHLIGHTS: This study investigates how neural networks address properties of child language. We focus on the Agent-First strategy in comprehension of Korean active transitive. Results show by-model/condition asymmetries against children's response patterns. This implies some limits of neural networks on revealing properties of child language.

How does linguistic context influence word learning?

While there are well-known demonstrations that children can use distributional information to acquire multiple components of language, the underpinnings of these achievements are unclear. In the current paper, we investigate the potential pre-requisites for a distributional learning model that can explain how children learn their first words. We review existing literature and then present the results of a series of computational simulations with Vector Space Models, a type of distributional semantic model used in Computational Linguistics, which we evaluate against vocabulary acquisition data from children. We focus on nouns and verbs, and we find that: (i) a model with flexibility to adjust for the frequency of events provides a better fit to the human data, (ii) the influence of context words is very local, especially for nouns, and (iii) words that share more contexts with other words are harder to learn.

Learning conversational dependency: Children's response using un in Japanese

This study investigates how Japanese-speaking children learn interactional dependencies in conversations that determine the use of un, a token typically used as a positive response for yes-no questions, backchannel, and acknowledgement. We hypothesise that children learn to produce un appropriately by recognising different types of cues occurring in the immediately preceding turns. We built a set of generalised linear models on the longitudinal conversation data from seven children aged 1 to 5 years and their caregivers. Our models revealed that children not only increased their un production, but also learned to attend relevant cues in the preceding turns to understand when to respond by producing un. Children increasingly produced un when their interlocutors asked a yes-no question or signalled the continuation of their own speech. These results illustrate how children learn the probabilistic dependency between adjacent turns, and become able to participate in conversational interactions.

Visual Heuristics for Verb Production: Testing a Deep-Learning Model With Experiments in Japanese

Tense/aspect morphology on verbs is often thought to depend on event features like telicity, but it is not known how speakers identify these features in visual scenes. To examine this question, we asked Japanese speakers to describe computer-generated animations of simple actions with variation in visual features related to telicity. Experiments with adults and children found that they could use goal information in the animations to select appropriate past and progressive verb forms. They also produced a large number of different verb forms. To explain these findings, a deep-learning model of verb production from visual input was created that could produce a human-like distribution of verb forms. It was able to use visual cues to select appropriate tense/aspect morphology. The model predicted that video duration would be related to verb complexity, and past tense production would increase when it received the endpoint as input. These predictions were confirmed in a third study with Japanese adults. This work suggests that verb production could be tightly linked to visual heuristics that support the understanding of events.

A comparative study of frequency effect on acquisition of grammar and meaning of words between Chinese and foreign learners of English language

Frequency effect on vocabulary acquisition has been widely investigated in second language acquisition (SLA) research, whereas comparative studies of vocabulary acquisition of learners from different language types, such as hieroglyphic writing and alphabetic writing, are still rarely found. This type of studies could be of great significance in exploring some unique characteristics of how second language learners of native languages of different writing perceive and acquire second language. Using artificial words of alphabetic writing and low-frequency English words as experimental materials, this study aims to compare the effect of frequency on the acquisition of grammar and meaning of alphabetic words between Chinese learners of the hieroglyphic native language and foreign learners of alphabetic native languages. Specifically, the study intends to find out whether frequency effect plays the key role in language acquisition; to what extent frequency effect affects language acquisition; and whether there are any differences between learners of different language types for vocabulary acquisition in terms of frequency effect. The results show that Chinese and foreign learners of English language have no significant differences as a whole in terms of type of languages affecting the acquisition of grammar and meaning of artificial words and English words, indicating the difference in the type of mother tongue might not be the factor causing differences on grammar and meaning acquisition of vocabulary. Learner types, language types, frequency and part of speech of a word have interaction effect toward the acquisition of grammar and meaning of a word. However, exposure frequency of vocabulary plays the determining role in the acquisition of grammar and meaning of words.

Acquisition of demonstratives in cross-linguistic perspective

This paper examines the acquisition of demonstratives (e.g., that, there) from a cross-linguistic perspective. Although demonstratives are often said to play a crucial role in L1 acquisition, there is little systematic research on this topic. Using extensive corpus data of spontaneous child speech, the paper investigates the emergence and development of demonstratives in three European (English, French, Spanish) and four non-European languages (Japanese, Chinese, Hebrew, Indonesian) between age 1;0 and 6;0. The data show that, across languages, demonstratives are among the earliest and most frequent child words, but their frequency decreases with age and MLU. As children grow older, they tend to use other types of referring terms (e.g., anaphoric pronouns) and other types of spatial expressions (e.g., adpositions). Considering these results, we hypothesize that children shift from using a body-oriented strategy of deictic communication to more abstract and disembodied strategies of encoding reference and space during the preschool years.

Two pathways in vocabulary development: Large-scale differences in noun and verb semantic structure

In adults, nouns and verbs have varied and multilevel semantic interrelationships. In children, evidence suggests that nouns and verbs also have semantic interrelationships, though the timing of the emergence of these relationships and their precise impact on later noun and verb learning are not clear. In this work, we ask whether noun and verb semantic knowledge in 16-30-month-old children tend to be semantically isolated from one another or semantically interacting from the onset of vocabulary development. Early word learning patterns were quantified using network science. We measured the semantic network structure for nouns and verbs in 3,804 16-30-month-old children at several levels of granularity using a large, open dataset of vocabulary checklist data. In a cross-sectional approach in Experiment 1, early nouns and verbs exhibited stronger network relationships with other nouns and verbs than expected across multiple network levels. Using a longitudinal approach in Experiment 2, we examined patterns of normative vocabulary development over time. Initial noun and verb learning was supported by strong semantic connections to other nouns, whereas later-learned words exhibited strong connections to verbs. Overall, these two experiments suggest that nouns and verbs demonstrate early semantic interactions and that these interactions impact later word learning. Early verb and noun learning is affected by the emergence of noun and verb semantic networks during early lexical development.

Semantic and Syntactic Properties of Words and the Receptive-Expressive Gap in Autistic and Non-Autistic Children

PURPOSE

The goal of this work was to examine the semantic and syntactic properties of the vocabularies of autistic and non-autistic infants and toddlers to see if children in these two groups know different kinds of words. We focused on both receptive and expressive vocabularies. For expressive vocabulary, we looked only at the "active" lexicon: Of those words that are already in children's receptive vocabulary, we asked which ones they also produce.

METHOD

We used an existing data set of 346 parent report vocabulary checklists (MacArthur-Bates Communicative Development Inventory: Words and Gestures) from 41 autistic and 27 non-autistic children at multiple timepoints between the ages of 6 and 43 months. We coded the words on the checklists for various semantic and syntactic properties and evaluated which properties predicted whether children understood and produced those words.

RESULTS

Overall, we replicated a common finding that autistic children have smaller receptive vocabularies than non-autistic children, but we found that of the words they understand, autistic children produce a similar proportion of those words as non-autistic children. While we found that some syntactic properties are more or less likely to be represented in children's early vocabularies (e.g., nouns are more likely to be understood and produced than words that are not nouns), these patterns did not differ across autistic and non-autistic children.

CONCLUSIONS

The semantic and syntactic compositions of autistic and non-autistic children's vocabularies are similar. Thus, while receptive vocabularies are relatively smaller for autistic children, they do not appear to have specific difficulty with words that have particular syntactic or semantic properties, or with adding words to the expressive vocabulary that they already understand.

Working memory training improves children's syntactic ability but not vice versa: A randomized control trial

We tested several hypotheses about the relation between syntax and working memory (WM). In a pretest/posttest randomized control trial, 104 native Cuban Spanish-speaking children (M_age = 7 years 2 months; 54 girls) took part in syntax training in their first language, syntax training in their second language, WM training, or no training (control). Compared with the control, children in the training conditions showed cognitive transfer from WM to syntax but not from syntax to WM. The result was most striking in the case of their first language, where WM training was as effective as language training in boosting syntactic performance. As well as establishing cognitive transfer at the group level, we also found that individual differences in WM performance, both at baseline and in training, predicted the extent to which children's syntax improved. The directionality of transfer, the group-level and individual-level results, established in the context of a randomized control design, all point to a strong causal role for domain-general cognition in the processes of language acquisition.

Korean-speaking children's constructional knowledge about a transitive event: Corpus analysis and Bayesian modelling

We investigate Korean-speaking children's knowledge about clause-level constructions involving a transitive event - active transitive and suffixal passive - through corpus analysis and Bayesian modelling. The analysis of Korean caregiver input and children's production in CHILDES revealed that the rates of constructional patterns produced by the children mirrored those uttered by the caregivers to a considerable degree and that the caregivers' use of case-marking was skewed towards single form-function pairings (despite the multiple form-function associations that the markers manifest). Based on these characteristics, we modelled a Bayesian learner by employing construction-based input (without considering lexical information). This simulation revealed the dominance of several constructional patterns, occupying most of the input, and their inhibitory effects on the development of the other patterns. Our findings illuminate how children shape clause-level constructional knowledge in Korean, an understudied language for this topic, as a function of input properties and domain-general learning capacities, appealing to the usage-based constructionist approach.

Early grammar-building in French-speaking deaf children with cochlear implants: A follow-up corpus study

BACKGROUND

One of the most consistent findings reported in the paediatric cochlear implant (CI) literature is the heterogeneity of language performance observed more in grammatical morphology than in lexicon or pragmatics. As most of the corpus studies addressing these issues have been conducted in English, it is unclear whether their results can be generalized to other languages. In particular, little is known about languages known for their grammatical complexity, such as French.

AIMS

The aim of this corpus study was to compare the productive use of function words (FWs) and some agreement features (AGRs) in children with CIs and children with typical development (TD) matched for mean length of utterance in words (MLU_words ), a general index of grammatical complexity, and auditory experience, as measured by hearing age (HA) and chronological age (CA), respectively.

METHODS & PROCEDURES

Natural speech samples from 116 monolingual French-speaking children, including 40 children with CIs followed longitudinally and 76 TD children, were collected. FWs and AGRs were analysed using a Part of Speech Tagger (POS-T) from the Child Language Data Exchange System (CHILDES).

OUTCOMES & RESULTS

The two groups differed by 3 years for HA and CA. No effect of family socio-economic status (SES) was found in the CI group. Stepwise regression analyses showed that the two groups did not share the same predictors of MLU_words : plurals and determiners predicted MLU_words in children with CIs, at 2 and 3 years of HA, whereas feminine markers and subject-pronouns were found to best predict MLU_words in TD children at 2 and 3 years of CA. Structural equation models (SEMs), a combination of confirmatory factor analysis (CFA) and path analysis, yielded a different hierarchical structure of grammatical relations (GRs). Selective difficulties affecting verbal clitics and other pronominal forms were found specifically in the CI group (object-pronouns, reflexive, relative and past participles). Dependency grammar analysis confirmed these contrasting developmental profiles in multiword utterances, such as preposition/nouns, subject/verbs, and verb/determiner/nouns.

CONCLUSIONS & IMPLICATIONS

Atypical grammatical patterns in children with CIs reflect a specific architecture of syntactic dependencies of FWs underpinning morphological complexity and syntactic connectivity. Clinical implications are discussed for assessment and intervention planning.

WHAT THIS PAPER ADDS

What is already known on this subject The productive use of FWs has been identified as a particular area of weakness in children with CIs compared with TD children. In addition, heterogenous grammatical performance has often been found after 1-3 years of CI use, regardless of demographic factors such as age at implantation, duration of deafness or SES. What this paper adds to existing knowledge Assessing the early building of FWs and AGRs in children with CIs helps to understand the syntactic complexity and hierarchical structure of their language. Since most corpus studies on grammatical morphology have been conducted in English, it is not clear whether their difficulties can be generalized to other languages. The French language has a system of FWs and inflections that determine the morphophonological properties of nominal and verbal forms. Early grammar learning in children with CIs born with profound deafness were compared with the two groups of TD children matched both for duration of auditory experience (i.e., HA of CI children, CA of TD children) and for MLU_words . We found a similar profile between groups at 2 years but not at 3 years for HA and CA. The two groups do not share the same predictors of MLU_words : namely, plurals and determiners for CI children versus feminine markers and subject pronouns for TD children. They show a different syntactic organization of GRs. Children with CIs struggle with selective difficulties affecting verbal clitics and pronominal forms (object-pronouns, reflexive, relative and past participles). Consistent with theories of morphophonological richness and syntactic connectivity, our results support the distributional learning hypothesis of language acquisition that infants and toddlers are sensitive to FWs and AGRs at an early age. Specific components of syntactic organization are disrupted in children with CIs. What are the potential or actual clinical implications of this work? This work has potential clinical implications because it unravels the limitations of morphophonological processing in children with CIs. Its results highlight a specific difficulty in learning FWs and AGRs in a verbal inflectional morphology context.

How infants' utterances grow: A probabilistic account of early language development

Why are children's first utterances short and ungrammatical, with some obvious constructions missing? What determines the lengthening of children's early utterances over time? The literature is replete with references to a one-word, a two-word, and a later multiword stage in language development, but with little empirical evidence, and with little account for how and why utterances grow. To address these questions, we analyze speech samples from 25 children between the ages of 14 and 43 months; we construct distributions of their utterances of lengths one to five by age. Our novel findings are that multiword utterances of different lengths appear early in acquisition and increase together until they reach relatively stable proportions similar to those found in parents' input. To explain such patterns, we develop a probabilistic computational model, VIRTUAL, that posits an interaction between a) varying, increasing resources from various developmental domains and b) target utterance lengths mirroring the input. VIRTUAL successfully accounts for most of the empirical patterns, suggesting a probabilistic and dynamic process that is nonetheless compatible with apparent distinct milestones in development. We provide a new, systematic way of showing how developmental cascade theories could work in language development. Our findings and model also suggest insights into syntactic, semantic, and cognitive development.

(In)frequently asked questions: On types of frequency and their role(s) in heritage language variability

In recent years, researchers have become increasingly interested in exploring frequency as a source of variability in heritage speakers' (HSs) knowledge of their heritage language (HL). While many of these studies acknowledge that frequency can affect the shape of HL grammars, there is still no clear consensus about (a) what "frequency" means in the context of HL acquisition and (b) how to operationalize its multiple subtypes. In this paper, we provide a critical overview of frequency effects in HL research and their relevance for understanding patterns of inter/intra-speaker variability. To do so, we outline how prior research has defined, measured, and tested frequency, and present-as well as evaluate-novel methodological approaches and innovations recently implemented in the study of frequency effects, including a new analysis of how self-reported lexical frequency reliably predicts HSs' production of subjunctive mood in Spanish. Our aim is to highlight the immense potential of such work for addressing long-standing questions about HL grammars and to propose new lines of inquiry that will open up additional pathways for understanding HL variability.

The Myth of Women's Advantage in Using Child-Directed Speech: Evidence of Women Versus Men in Single-Sex-Parent Families

PURPOSE

Differences between child-directed speech (CDS) by women and men are generally explained by either biological-evolutionary or gender-social theories. It is difficult to tease these two explanations apart for different-sex-parent families because women are usually also the main caregivers. Thus, this study aims to examine the influence of parental sex on CDS by investigating men and women who are in same-sex-parent families.

METHOD

Twenty same-sex-parent families participated in the study-10 families in which the parents were two men and 10 families in which the parents were two women. The families were matched for toddler age (range: 9-24 months) and sex. CDS was recorded using the Language Environment Analysis (LENA) device for 16 hr during a day. Each parent was also audio-recorded during a 30-min play session with his or her child.

RESULTS

No difference was found between men and women across all the LENA measures, namely, adult word count, conversational turns count, and child vocalization count. The analysis of speech samples during parent-child play showed no difference between men and women in mean length of utterance and number of nouns, verbs, and adjectives. Pragmatic speech acts of initiations, responses to infants' actions, or vocalizations were similar in both sexes. Women used more "teaching" utterances than men, and men who were main caregivers used more "teaching" utterances than men who were secondary caregivers. Across both sexes, secondary caregivers used more "requests for actions" compared to main caregivers.

CONCLUSIONS

The present findings support a functional-social approach and not a biological approach for explaining the use of CDS by men and women. These findings have clinical implications on the involvement of men in early intervention programs.

Estimations of child linguistic productivity controlling for vocabulary and sample size

Children's use of present tense suffixes is less productive than that of their parents, after correcting for sample size and lexical knowledge, according to a recently established approach for the study of inflectional productivity. This article expands on this technique by providing precise estimates of early grammatical productivity through systematic random sampling and allowing for developmental assessment. Two cross-linguistic comparisons are given in the results of this study. Two Spanish-speaking children and their parents are compared with four English-speaking children and their parents. The second comparison examines potential differences in productivity throughout developmental stages using the same six children's speech. The findings indicate that Spanish-acquiring children are less productive than their parents while utilising the paradigm under study, but that productivity levels increase over time. In contrast, the English-speaking children's morphosyntactic production mirrors that of their parents. Although the primary focus of this research is methodological, these findings have consequences for theoretical theories arguing either rule abstraction or a restricted generalisation of early exemplars.

Reference production in Mandarin–English bilingual preschoolers: Linguistic, input, and cognitive factors

Reference in extended discourse is vulnerable to delayed acquisition in early childhood. Although recent research has increasingly focused on effects of linguistic, input, and cognitive factors on reference production, these studies are limited in number and the results are mixed. The present study provides insight into bilingual reference production by investigating how production of referring expressions in the two languages of preschool bilingual children may be influenced by structural similarities and differences between the languages, frequency of referring expressions in maternal input, amount of exposure to each of the languages, and working memory capacity. Using two stories in the Multilingual Assessment Instrument for Narratives (MAIN), we examined character introduction and re-introduction in oral narratives of 4–6-year-old Singaporean bilingual children acquiring Mandarin Chinese and English (n = 21), and in child-directed speech of the mothers (n = 17). The children’s language exposure, executive function, and general bilingual proficiency were also recorded or directly tested through structured interviews with the parents or standardized assessments with the children. Data collection was conducted remotely in real time over a video-conferencing platform, supplemented by on-site audio recording to ensure sound quality. Results showed prolonged development in the production of felicitous REs for first mentions and over-reliance on overt marking of definiteness in our bilingual children. Mixed modeling revealed that frequency of felicitous REs in the input predicted children’s production of felicitous REs across languages and discourse functions, with a modulating effect of working memory. Overall, our findings are consistent with previous ones in that reference production is vulnerable in early Mandarin-English bilinguals in a multilingual society. This study also presents novel evidence that structural frequency in the input interacts with working memory in shaping patterns of reference production in bilingual children.

Converging Evidence of Underlying Competence: Comprehension and Production in the Acquisition of Spanish Subject-Verb Agreement

A surprising comprehension-production asymmetry in subject-verb (SV) agreement acquisition has been suggested in the literature, and recent research indicates that task-specific as well as language-specific features may contribute to this apparent asymmetry across languages. The present study investigates when during development children acquiring Mexican Spanish gain competence with 3^rd-person SV agreement, testing production as well as comprehension in the same children aged between 3;6 and 5;7 years, and whether comprehension of SV agreement is modulated by the sentential position of the verb (i.e., medial vs. final position). Accuracy and sensitivity analyses show that comprehension performance correlates with SV agreement production abilities, and that comprehension of singular and plural third-person forms is not influenced by the sentential position of the agreement morpheme. Issues of the appropriate outcome measure and the role of structural familiarity in the development of abstract representations are discussed.

Statistical Learning of Language: A Meta-Analysis Into 25 Years of Research

Statistical learning is a key concept in our understanding of language acquisition. Ample work has highlighted its role in numerous linguistic functions-yet statistical learning is not a unitary construct, and its consistency across different language properties remains unclear. In a meta-analysis of auditory-linguistic statistical learning research spanning the last 25 years, we evaluated how learning varies across different language properties in infants, children, and adults and surveyed the methodological trends in the literature. We found robust learning across stimuli (syllables, words, etc.) in infants, and across stimuli and structures (adjacent dependencies, non-adjacent dependencies, etc.) in adults, with larger effect sizes when multiple cues were present. However, the analysis also showed significant publication bias and revealed a tendency toward using a narrow range of simplified language properties, including in the strength of the transitional probabilities used during training. Bayes factor analyses revealed prevalent data insensitivity of moderators commonly hypothesized to impact learning, such as the amount of exposure and transitional probability strength, which contradict core theoretical assumptions in the field. Methodological factors, such as the tasks used at test, also significantly impacted effect sizes in adults and children, suggesting that choice of task may critically constrain current theories of how statistical learning operates. Collectively, our results suggest that auditory-linguistic statistical learning has the kind of robustness needed to play a foundational role in language acquisition, but that more research is warranted to reveal its full potential.

Acquisition of variability in Akan Phonology: Labio-palatalized consonants and front rounded vowels

This paper addresses how input variability in the adult phonological system is mastered in the output of young children in Akan, a Kwa language spoken in Ghana, involving variability between labio-palatalized consonants and front rounded vowels. The high-frequency variant involves a complex consonant which is expected to be mastered late, while the low-frequency variant involves a front rounded vowel which is expected to be mastered relatively early. Late mastery of complex consonants was confirmed. The high-frequency labiopalatalized-consonant variant was absent at age 3 and not yet mastered even at age 5. All children produced the easier-to-produce low-frequency front-rounded-vowel variant, most at far greater frequency than in adult speech, implying that a child's output limitations can affect which variant the child targets for production. Modular theories, in which phonological plans reflect only the characteristics of adult input, fail to account for our results. Non-modular theories are implicated.

The influence of prominence cues in 7- to 10-year-olds' pronoun resolution: Disentangling order of mention, grammatical role, and semantic role

In two visual world experiments we disentangled the influence of order of mention (first vs. second mention), grammatical role (subject vs object), and semantic role (proto-agent vs proto-patient) on 7- to 10-year-olds' real-time interpretation of German pronouns. Children listened to SVO or OVS sentences containing active accusative verbs (küssen "to kiss") in Experiment 1 (N = 72), or dative object-experiencer verbs (gefallen "to like") in Experiment 2 (N = 64). This was followed by the personal pronoun er or the demonstrative pronoun der. Interpretive preferences for er were most robust when high prominence cues (first mention, subject, proto-agent) were aligned onto the same entity; and the same applied to der for low prominence cues (second mention, object, proto-patient). These preferences were reduced in conditions where cues were misaligned, and there was evidence that each cue independently influenced performance. Crucially, individual variation in age predicted adult-like weighting preferences for semantic cues (Schumacher, Roberts & Järvikivi, ).

Input effects in the acquisition of verb inflection: Evidence from Emirati Arabic

This study investigates the acquisition of the Imperfective verb inflection paradigm in Emirati Arabic (EA), to determine whether the learning process is sensitive to the phonological and typological properties of the input. We collected data from 48 participants aged 2;7 to 5;9 years, using an elicited production paradigm. Input frequencies of inflectional contexts, verb types and tokens were obtained from corpora of child-directed and adult EA. Children's accuracy was inversely related to the input frequency of inflectional contexts, but not related to type and token frequency or phonological neighborhood density. Token frequency interacted with age, such that younger children performed considerably worse on low-frequency tokens, but older children performed equally well on high- and low-frequency tokens. We conclude that learning is input-driven, but that a sufficiently regular paradigm allows children to eventually generalise across all items earlier than in previously studied European languages.

Passive Voice Comprehension during Thematic-Role Assignment in Russian-Speaking Children Aged 4-6 Is Reflected in the Sensitivity of ERP to Noun Inflections

Children tend to rely on semantics rather than syntax during sentence comprehension. In transitive sentences, with no reliance on semantics, the syntax-based strategy becomes critical. We aimed to describe developmental changes of brain mechanisms for syntax processing in typically developing (TD) four to six year old’s. A specially designed sentence-picture matching task using active (AV) and passive (PV) voice enforced children to use grammar cues for sentence comprehension. Fifty children with above >60% level of accuracy in PV sentences comprehension demonstrated brain sensitivity to voice grammar markers-inflections of the second noun phrase (NP2), which was expressed in a greater event-related potentials (ERP) amplitude to PV vs. AV sentences in four-, five-, and six-year-old children. The biphasic positive-negative component at 200−400 ms was registered in the frontocentral and bilateral temporoparietal areas. Only in six-year-old children P600 was registered in the right temporoparietal area. LAN-like negativity seems to be a mechanism for distinguishing AV from PV in the early stages of mastering syntax processing of transitive sentences in four to five year old children. Both behavioral and ERP results distinguished six-year-olds from four-year-old’s and five-year-old’s, reflecting the possible transition to the “adult-like” syntax-based thematic role assignment.

The function and evolution of child-directed communication

Humans communicate with small children in unusual and highly conspicuous ways (child-directed communication (CDC)), which enhance social bonding and facilitate language acquisition. CDC-like inputs are also reported for some vocally learning animals, suggesting similar functions in facilitating communicative competence. However, adult great apes, our closest living relatives, rarely signal to their infants, implicating communication surrounding the infant as the main input for infant great apes and early humans. Given cross-cultural variation in the amount and structure of CDC, we suggest that child-surrounding communication (CSC) provides essential compensatory input when CDC is less prevalent-a paramount topic for future studies.

Learning speaker- and addressee-centered demonstratives in Ticuna

This study investigated the acquisition of demonstratives (e.g., this/that, here/there) by 45 children (1;0 - 4;11) learning Ticuna, an Indigenous Amazonian language with an unusually complex demonstrative system. I analyzed 89 10-minute samples from video recordings of child-caregiver interaction, examining how often children and caregivers produced each demonstrative type, as well as relationships among children's age, children's demonstrative production, and caregivers' production. Caregivers' demonstrative production displayed few relationships with children's age or production. Children produced speaker-proximal and speaker-distal demonstratives (this near me, that far from me) earlier in developmental time than addressee-proximal demonstratives (that near you), and nominal (this/that) demonstratives earlier than locative (here/there) ones. Compared to caregivers, children overused speaker-proximal demonstratives, but used other demonstrative types with adult-like frequency beginning at 2;0. These results support the view that cognitive biases toward egocentric, proximal, and semantically simpler items substantially influence children's acquisition of demonstratives.

The Phonological Development of Mandarin Voiceless Affricates in Three- to Five-Year-Old Children

This study investigates the phonological development of Mandarin voiceless affricates produced by Mandarin-speaking children. Thirty-six monolingual Mandarin-speaking children and twelve adults participated in a speech production task. Auditory-based transcription analysis and acoustic analysis were utilized to quantify the relative order of affricate acquisition. Both methods yielded earlier acquisition of alveopalatal affricates at age three than retroflex and alveolar affricates, whereas they differed in the acquisition order of retroflex and alveolar affricates. The former revealed that both retroflex and alveolar affricates were acquired at age five, regardless of aspiration, while the latter yielded earlier acquisition of retroflex than alveolar affricates. Possible reasons for the discrepancy are discussed in relation to the different nature of the two methods. Overall, the observed acquisition order of Mandarin voiceless affricates suggests that child speech development is a complex process, and is influenced by various factors including oromotor maturation and language-specific phoneme frequencies in the ambient language.

Word Segmentation Cues in German Child-Directed Speech: A Corpus Analysis

To acquire language, infants must learn to segment words from running speech. A significant body of experimental research shows that infants use multiple cues to do so; however, little research has comprehensively examined the distribution of such cues in naturalistic speech. We conducted a comprehensive corpus analysis of German child-directed speech (CDS) using data from the Child Language Data Exchange System (CHILDES) database, investigating the availability of word stress, transitional probabilities (TPs), and lexical and sublexical frequencies as potential cues for word segmentation. Seven hours of data (~15,000 words) were coded, representing around an average day of speech to infants. The analysis revealed that for 97% of words, primary stress was carried by the initial syllable, implicating stress as a reliable cue to word onset in German CDS. Word identity was also marked by TPs between syllables, which were higher within than between words, and higher for backwards than forwards transitions. Words followed a Zipfian-like frequency distribution, and over two-thirds of words (78%) were monosyllabic. Of the 50 most frequent words, 82% were function words, which accounted for 47% of word tokens in the entire corpus. Finally, 15% of all utterances comprised single words. These results give rich novel insights into the availability of segmentation cues in German CDS, and support the possibility that infants draw on multiple converging cues to segment their input. The data, which we make openly available to the research community, will help guide future experimental investigations on this topic.

Spontaneous verbal repetition in toddler-adult conversations: a longitudinal study with Spanish-speaking two- year-olds

The role of children's verbal repetition of parents' utterances on vocabulary growth has been well documented (Masur, 1999). Nevertheless, few studies have analyzed adults' and children's spontaneous verbal repetition around the second birthday distinguishing between the types of repetition. We analyzed longitudinally Spanish-speaking parent-child dyads during spontaneous interaction at 21, 24 and 30 months. Linguistic level was measured using the Spanish version of the MacArthur CDI (López-Ornat et al., 2005). Children's and adults' repetitions are about 17% of the speech. Children repeated adults' utterances in a reduced manner whereas adults produced more extended repetitions. Adults' rate of repetition predicted children's linguistic level at 30 months. Children's rate of repetition did not predict linguistic level. These results suggest that parents adapt their speech to children's communicative abilities. Since children's rate of repetition did not predict linguistic level, we suggest that verbal imitation plays an indirect and complex role in communicative development.

Early Word Order Usage in Preschool Mandarin-Speaking Typical Children and Children With Autism Spectrum Disorder: Influences of Caregiver Input?

This study explores the emergence and productivity of word order usage in Mandarin-speaking typically-developing (TD) children and children with autism spectrum disorder (ASD), and examines how this emergence relates to frequency of use in caregiver input. Forty-two caregiver-child dyads participated in video-recorded 30-min semi-structured play sessions. Eleven children with ASD were matched with 10 20-month-old TD children and another 11 children with ASD were matched with 10 26-month-old TD children, on expressive language. We report four major findings: (1) Preschool Mandarin-speaking children with ASD produced word order structures with pervasive ellipsis at similar rates to language-matched TD children, but also displayed differences from TD children in their usage of SVt and VtO frames; (2) Grammatical productivity was observed in both TD children and children with ASD; moreover, children with ASD with higher expressive language produced less stereotyped language; (3) Both TD children and children with ASD heard a range of word orders in their caregivers’ input, with TD children’s input greater in amount and complexity; however, caregivers of both groups also showed no age/language-related changes in word order usage; (4) Few word-order-specific correlations emerged between caregivers and their children; however, strong correlations were observed for mean length of utterances (MLU) for both groups: Caregivers who produced longer/more complex utterances had children who did the same. Taken together, it seems that despite their pragmatic deficits, the early grammatical knowledge of word order in Mandarin-exposed children with ASD is well preserved and in general follows the typical developmental pattern. Moreover, caregiver input is broadly rather than finely tuned to the linguistic development of TD children and children with ASD, and plays a more important role in children’s general syntactic development than in specific word order acquisition. Thus, early word order usage in preschool Mandarin-speaking TD children and children with ASD may be influenced by both caregiver input and child abilities.

Phonological neighborhood measures and multisyllabic word acquisition in children

Multisyllabic words constitute a large portion of children's vocabulary. However, the relationship between phonological neighborhood density and English multisyllabic word learning is poorly understood. We examine this link in three, four and six year old children using a corpus-based approach. While we were able to replicate the well-accepted positive association between CVC word acquisition and neighborhood density, no similar relationship was found for multisyllabic words, despite testing multiple novel neighborhood measures. This finding raises the intriguing possibility that phonological organization of the mental lexicon may play a fundamentally different role in the acquisition of more complex words.