Children are believed to construct their causal theories through talk and interaction, but with the exception of a few studies, little or nothing is known about how young children justify and build theories of the world together with same-age peers through naturally occurring interaction, Children's sensitivity to when a pair or group of interlocutors who interact frequently together feel that a justification is needed, is an index of developing pragmatic competence (Goetz & Shatz, 1999) and may be influenced by interactive goals and gender identity positioning. Studies suggest that salient contexts for justifications for young children are disagreement and control (e.g. Veneziano & Sinclair, 1995) but researchers have been less recognizant of ‘situations in which partners verbally assist in the construction of justifications as a means to maintain contact or create solidarity’ (Goetz & Shatz, 1999: 722) as contexts for justifications. The present study examined the spontaneously produced justification constructions in the naturally occurring free play of five friendship groups of preschool-aged children (aged from 3 ; 6 to 5 ; 4), in terms of the motivating context of the justification, marking of the causal relationship with a connective, and causal theories accessed in the talk. Partner expansion (validating justifications) was a salient motivating context for justifications, especially in the talk of friendship groups of girls, and seemed to privilege greater marking of the causal relationship with a connective and less arbitrary reasoning. One group of girls varied their use of validating justifications depending on the theme of play. Results are discussed in terms of the implications of use of validating justifications for children's causal theory building with peers, linguistic development, and pragmatic development.

This study examines the interacting roles of implicational markedness and frequency from the joint perspectives of formal linguistic theory, phonological acquisition and computational modeling. The hypothesis that child grammars are rankings of universal constraints, as in Optimality Theory (Prince & Smolensky, 1993/2004), that learning involves a gradual transition from an unmarked initial state to the target grammar, and that order of acquisition is guided by frequency, along the lines of Levelt, Schiller & Levelt (2000), is investigated. The study reviews empirical findings on syllable structure acquisition in Dutch, German, French and English, and presents novel findings on Polish. These comparisons reveal that, to the extent allowed by implicational markedness universals, frequency covaries with acquisition order across languages. From the computational perspective, the paper shows that interacting roles of markedness and frequency in a class of constraint-based phonological learning models embody this hypothesis, and their predictions are illustrated via computational simulation.

This study explores parents' and children's use of and response to direct or indirect behaviour regulation in a family context. Ten families with two children each were divided into two groups depending on the age of the children (6–7 and 10–11 years or 10–11 and 13–14 years). Video-recorded regulatory dinner talk was transcribed, coded and analysed with regard to directness or indirectness in relation to behavioural outcome. Dinner talk was predominantly direct, but younger children were addressed by direct regulators as two-thirds of all regulators, whereas the opposite was seen with older children. Though children also tended to be direct, younger children used three times as many direct regulators as older ones. Compliance appeared in two-thirds of all direct regulators, but almost one-half of all indirect regulators were not complied with. Differences between groups were furthermore distinguished by instances of compliance: those who were most non-compliant were the children in group 2.

The aims of this study were to investigate whether specific linguistic difficulties in preterm children persist at eight years and to examine the interrelationships between language and literacy in this population, compared with a control group of full-term children. Sixty-eight monolingual Italian preterms and 26 chronologically matched controls were recruited. Language (grammar comprehension, lexical production and phonological awareness), literacy (reading comprehension, reading and writing) and general cognitive development were investigated. Results showed no general delay in preterms, but slight difficulties in specific linguistic abilities (grammar, lexicon, phoneme synthesis and deletion of the first syllable), more difficulties in literacy (speed in reading and accuracy in writing) and certain correlations among competencies turning out to be different from the control group. In conclusion, our study established that a partially atypical trajectory emerged in preterms, showing specific long-term effects of preterm birth on language and literacy development.

Recent analyses have revealed that child-directed speech contains distributional regularities that could, in principle, support young children's discovery of distinct grammatical categories (noun, verb, adjective). In particular, a distributional unit known as the frequent frame appears to be especially informative (Mintz, 2003). However, analyses have focused almost exclusively on the distributional information available in English. Because languages differ considerably in how the grammatical forms are marked within utterances, the scarcity of cross-linguistic evidence represents an unfortunate gap. We therefore advance the developmental evidence by analyzing the distributional information available in frequent frames across two languages (Spanish and English), across sentence positions (phrase medial and phrase final), and across grammatical forms (noun, verb, adjective). We selected six parent–child corpora from the CHILDES database (three English; three Spanish), and analyzed the input when children were aged 2 ; 6 or younger. In each language, frequent frames did indeed offer systematic cues to grammatical category assignment. We also identify differences in the accuracy of these frames across languages, sentences positions and grammatical classes.

We present a hierarchical Bayesian framework for modeling the acquisition of verb argument constructions. It embodies a domain-general approach to learning higher-level knowledge in the form of inductive constraints (or overhypotheses), and has been used to explain other aspects of language development such as the shape bias in learning object names. Here, we demonstrate that the same model captures several phenomena in the acquisition of verb constructions. Our model, like adults in a series of artificial language learning experiments, makes inferences about the distributional statistics of verbs on several levels of abstraction simultaneously. It also produces the qualitative learning patterns displayed by children over the time course of acquisition. These results suggest that the patterns of generalization observed in both children and adults could emerge from basic assumptions about the nature of learning. They also provide an example of a broad class of computational approaches that can resolve Baker's Paradox.

We investigated developmental changes during the transition from one-word to two-word production, focusing on strategies to lengthen utterances phonologically and to control utterances suprasegmentally. We hypothesized that there is a period of reorganization at the onset of word combinations indicated by decreases in both filler syllables (Fillers) and final syllable lengthening (FSL). The data are from a visually impaired child (Seth) between 1 ; 6.21 and 1 ; 10.26. Seth produced many Fillers until 1 ; 9 when their number decreased for about two weeks after which they changed in nature. FSL was observed until 1 ; 8, but diminished at 1 ; 9. These two regressions coincide with the onset of word combination.

This study explores the form of representational gestures produced by forty-five hearing children (age range 2 ; 0–3 ; 1) asked to label pictures in words. Five pictures depicting objects and five pictures depicting actions which elicited more representational gestures were chosen for more detailed analysis. The range of gestures produced for each item varied from 3 to 27 for a total of 128 gestures. Gestures have been analyzed with the same parameters used to describe signs produced by deaf children: handshape, location and movement. Results show that gestures for a given picture exhibit similarities in many of the parameters across children. Some motor characteristics found in the production of hearing toddlers' gestures are similar to those described for early signs. Implications of this similarity between gestural and signed linguistic representations in young children are discussed.

This paper reports the results of a longitudinal case study examining the acquisition of the English voice system by a three-year-old native speaker of Dutch. The study aims to examine whether the child develops two different phonetic systems or uses just one system for both languages, and compares the early L2 acquisition process with L1, simultaneous bilingual and late L2 acquisition. The results reveal that the child successfully acquires the English contrast between short-lag and long-lag stops, but gradually changes the Dutch system, which contrasts prevoiced with short-lag stops, into the direction of the English system.

The phonetic characteristics of canonical babbling produced by Korean- and English-learning infants were compared with consonant and vowel frequencies observed in infant-directed speech produced by Korean- and English-speaking mothers. For infant output, babbling samples from six Korean-learning infants were compared with an existing English babbling database (Davis & MacNeilage, 1995). For ambient language comparisons, consonants and vowels in ten Korean and ten English infant-directed speech (IDS) samples were analyzed. The two infant groups demonstrated similar consonant patterns, but showed different vowel patterns from one another. For both languages, infant vowel patterns were related to those of ambient language IDS. Ambient language patterns were manifested in infant vowel output, perhaps because vowels are more perceptually and motorically available in the input and output capacities of babbling infants.

In this study, we use corpus analysis and computational modelling techniques to compare two recent accounts of the OI stage: Legate & Yang's (2007) Variational Learning Model and Freudenthal, Pine & Gobet's (2006) Model of Syntax Acquisition in Children. We first assess the extent to which each of these accounts can explain the level of OI errors across five different languages (English, Dutch, German, French and Spanish). We then differentiate between the two accounts by testing their predictions about the relation between children's OI errors and the distribution of infinitival verb forms in the input language. We conclude that, although both accounts fit the cross-linguistic patterning of OI errors reasonably well, only MOSAIC is able to explain why verbs that occur more frequently as infinitives than as finite verb forms in the input also occur more frequently as OI errors than as correct finite verb forms in the children's output.

This study examines potential predictors of ‘precocious talking’ (expressive language ⩾90th percentile) at one and two years of age, and of ‘stability’ in precocious talking across both time periods, drawing on data from a prospective community cohort comprising over 1,800 children. Logistic regression was used to examine the relationship between precocious talking and the following potential predictors: gender, birth order, birth weight, non-English speaking background, socioeconomic status, maternal age, maternal mental health scores, and vocabulary and educational attainment of parents. The strongest predictors of precocity (being female and having a younger mother) warrant further exploration. Overall, however, it appears that precocity in early vocabulary development is not strongly influenced by the variables examined, which together explained just 2·6% and 1% of the variation at 1 ; 0 and 2 ; 0 respectively.

We examined whether preschoolers' ontological knowledge would influence lexical extension. In Experiment 1, four-year-olds were presented with a novel label for either an object with eyes described as an animal, or the same object without eyes described as a tool. In the animal condition, children extended the label to similar-shaped objects, whereas in the tool condition, children extended the label to similar-function objects. In Experiment 2, when four-year-olds were presented with objects with eyes described as tools, they extended the label on the basis of shared function. These experiments suggest that preschoolers' conceptual knowledge guides their lexical extension.

In this work, we examine a context in which a conflict arises between two roles that infant-directed speech (IDS) plays: making language structure salient and modeling the adult form of a language. Vowel devoicing in fluent adult Japanese creates violations of the canonical Japanese consonant–vowel word structure pattern by systematically devoicing particular vowels, yielding surface consonant clusters. We measured vowel devoicing rates in a corpus of infant- and adult-directed Japanese speech, for both read and spontaneous speech, and found that the mothers in our study preserve the fluent adult form of the language and mask underlying phonological structure by devoicing vowels in infant-directed speech at virtually the same rates as those for adult-directed speech. The results highlight the complex interrelationships among the modifications to adult speech that comprise infant-directed speech, and that form the input from which infants begin to build the eventual mature form of their native language.

It is as yet unclear whether the benefits of early linguistic experiences can be maintained without at least some minimal continued exposure to the language. This study compared 12 adults adopted from Korea to the US as young children (all but one prior to age one year) to 13 participants who had no prior exposure to Korean to examine whether relearning can aid in accessing early childhood language memory. All 25 participants were recruited and tested during the second week of first-semester college Korean language classes. They completed a language background questionnaire and interview, a childhood slang task and a Korean phoneme identification task. Results revealed an advantage for adoptee participants in identifying some Korean phonemes, suggesting that some components of early childhood language memory can remain intact despite many years of disuse, and that relearning a language can help in accessing such a memory.

To express object transfer, Cantonese-speakers use a ‘ditransitive’ ([V–R–T] or [V–T–R] where V=Verb, T=Theme, R=Recipient), or a more complex prepositional/serial-verb (P/SV) construction. Clausal elements in Cantonese datives can be optional (resulting in ‘full’ versus ‘non-full’ forms) or appear in variant orders (full non-canonical and full canonical). We report on usage of dative constructions with the word bei2 ‘to give’ in 86 parents and 53 three-year-old children during conversations. The parents used more P/SV than ditransitive bei2-datives, and vice versa for the children. Both groups showed a similar usage pattern of optional elements and variant structures in their ditransitive and P/SV bei2-datives. The roles of multiple construction types, optional elements and variant structures in children's learning of bei2-dative constructions are described.

This paper reports progress in developing a computer model of language acquisition in the form of (1) a generative grammar that is (2) algorithmically learnable from realistic corpus data, (3) viable in its large-scale quantitative performance and (4) psychologically real. First, we describe new algorithmic methods for unsupervised learning of generative grammars from raw CHILDES data and give an account of the generative performance of the acquired grammars. Next, we summarize findings from recent longitudinal and experimental work that suggests how certain statistically prominent structural properties of child-directed speech may facilitate language acquisition. We then present a series of new analyses of CHILDES data indicating that the desired properties are indeed present in realistic child-directed speech corpora. Finally, we suggest how our computational results, behavioral findings, and corpus-based insights can be integrated into a next-generation model aimed at meeting the four requirements of our modeling framework.

We investigated whether access to a sign language affects the development of pragmatic competence in three groups of deaf children aged 6 to 11 years: native signers from deaf families receiving bimodal/bilingual instruction, native signers from deaf families receiving oralist instruction and late signers from hearing families receiving oralist instruction. The performance of these children was compared to a group of hearing children aged 6 to 7 years on a test designed to assess sensitivity to violations of conversational maxims. Native signers with bimodal/bilingual instruction were as able as the hearing children to detect violations that concern truthfulness (Maxim of Quality) and relevance (Maxim of Relation). On items involving these maxims, they outperformed both the late signers and native signers attending oralist schools. These results dovetail with previous findings on mindreading in deaf children and underscore the role of early conversational experience and instructional setting in the development of pragmatics.