This paper examines the role of age, working memory span and phonological ability in the mastery of ten different grammatical constructions. Six- through eleven-year-old children (n=68) and adults (n=19) performed a grammaticality judgment task as well as tests of working memory capacity and receptive phonological ability. Children showed early mastery of some grammatical structures (e.g. word order, article omissions) while even the oldest children differed from adults on others (e.g. past tense, third person singular agreement). Working memory capacity and phonological ability accounted for variance in grammaticality judgments above and beyond age effects. In particular, working memory capacity correlated with structures involving verb morphology and word order; phonological ability was important for structures with low phonetic substance. Children's relative difficulty with the different constructions showed parallels to adult performance under memory load stress, indicating working memory capacity may be a limiting factor in their performance. Implications for performance by memory and phonologically impaired populations are discussed.

Previous studies show that young monolingual children's ability to ‘fast map’ new word forms is closely associated with both their age and existing vocabulary knowledge. In this study we investigate potential relationships between age, fast mapping skills and existing vocabulary knowledge in both languages of developing bilingual preschool children. Participants were twenty-six typically developing children, ages 3 ; 0 to 5 ; 3. All children learned Hmong as their primary home language (L1) and English as a second language (L2). Fast mapping and vocabulary knowledge tasks were administered in L1 and L2. For vocabulary knowledge, scores were comparable in L1 and L2; for fast mapping, scores were somewhat greater in L1 than L2. In contrast to previous findings with monolingual children, fast mapping performance was not related to age or existing vocabulary knowledge in either Hmong or English. There were, however, significant positive and negative cross-language correlations between L1 fast mapping and L2 vocabulary.

This paper outlines functionally motivated quantifiable criteria for characterizing different facets of discourse – global-level principles, categories of referential content, clause-linking complex syntax, local linguistic expression and overall discourse stance – in relation to the variables of development, genre and modality. Concern is with later, school-age language development, in the conviction that the long developmental route of language acquisition can profitably be examined in the context of extended discourse. Findings are reviewed from a cross-linguistic project that elicited narrative and expository texts in both speech and writing at four age groups: (9–10 years, 12–13, 16–17 and adults). Clear developmental patterns emerge from middle childhood to adulthood, with significant shifts in adolescence; global-level text organization is mastered earlier in narratives than in expository essays, but the latter promote more advanced use of local-level lexicon and syntax; and spoken texts are more spread out than their denser written counterparts in clause-linkage, referential content and lexical usage. These and other findings are discussed in terms of the growth and reorganization of knowledge about types of discourse and text-embedded language use.

The acquisition of reference involves both morphosyntax and pragmatics. This study investigates whether Dutch, English and French two- to three-year-old children differentiate in their use of determiners between non-specific/specific reference, newness/givenness in discourse and mutual/no mutual knowledge between interlocutors. A brief analysis of the input shows a clear association between form and function, although there are some language differences in this respect. As soon as determiner use can be statistically analyzed, the children show a relatively adult-like pattern of association for the distinctions of non-specific/specific and newness/givenness. The distinction between mutual/no mutual knowledge appears later. Reference involving no mutual knowledge is scarcely evidenced in the input and barely used by the children at this age. The development of associations is clearly related to the rate of determiner development, the French being quickest, then the English, then the Dutch.

Two-year-old children often start asking questions with where. In this study we test whether children understand where to mean route or absolute location and whether the size of the space or elevation made a difference. Previous research has documented developmental changes over the preschool years in children's non-verbal spatial reasoning. Forty-eight children between two and five years of age were interviewed. We asked them to point in response to where questions about an object, rooms on the same floor and on a different floor. All children pointed to the location of the hidden objects. The youngest children pointed to the route to rooms while the oldest children were more likely to point to the location of rooms. With age, the children gradually used more spatial location terms than deictic terms in response to where. These results suggest that children's meaning of where initially differs for different sized spaces and developmental changes reflect non-verbal cognition.

Studies examining factors that influence when words are learned typically investigate one lexical category or a small set of words. We provide the first evaluation of the relation between input frequency and age of acquisition for a large sample of words. The MacArthur-Bates Communicative Development Inventory provides norming data on age of acquisition for 562 individual words collected from the parents of children aged 0 ; 8 to 2 ; 6. The CHILDES database provides estimates of frequency with which parents use these words with their children (age: 0 ; 7–7 ; 5; mean age: 36 months). For production, across all words higher parental frequency is associated with later acquisition. Within lexical categories, however, higher frequency is related to earlier acquisition. For comprehension, parental frequency correlates significantly with the age of acquisition only for common nouns. Frequency effects change with development. Thus, frequency impacts vocabulary acquisition in a complex interaction with category, modality and developmental stage.

Past research has indicated that English-learning infants begin segmenting words from speech by 7·5 months of age (Jusczyk & Aslin, 1995). More recent work has demonstrated, however, that 7·5-month-olds' segmentation abilities are severely limited. For example, the ability to segment vowel-initial words from speech reportedly does not appear until 13·5 to 16 months of age (Mattys & Jusczyk, 2001; Nazzi, Dilley, Jusczyk, Shattuck-Hufnagel & Jusczyk, 2005). In this paper, we report on three experiments using the Headturn Preference procedure that investigate both phonetic and phonological factors influencing 11-month-olds' segmentation of vowel-initial words from speech. We replicate earlier findings suggesting that infants have difficulty segmenting vowel-initial words from speech. In addition we extend these findings by demonstrating that under certain conditions, infants are capable of segmenting vowel-initial words from speech at a much younger age than earlier studies have reported. Our findings suggest that infants' ability to segment vowel-initial words from speech is tightly constrained by acoustic-phonetic factors such as pitch movement at the onset of vowel-initial words and segmental strengthening. These experiments underscore the complexity of early word segmentation, and highlight the importance of including contextual factors in developmental models of word segmentation.

Rapid acquisition of linguistic categories or constructions is sometimes regarded as evidence of innate knowledge. In this paper, we examine Polish children's early understanding of an idiosyncratic, language-specific construction involving the instrumental case – which could not be due to innate knowledge. Thirty Polish-speaking children aged 2 ; 6 and 3 ; 2 participated in a elicited production experiment with novel verbs that were demonstrated as taking nouns in the instrumental case as patients. Children heard the verbs in sentences with either masculine or feminine nouns (which take different endings in the instrumental case), and were tested with new nouns of the same and of the opposite gender. In both age groups, a substantial majority of children succeeded in generalizing from one gendered form of the instrumental case to the other (especially to the masculine), thus indicating that they have some kind of abstract understanding of the instrumental case in this construction. This relatively early abstract knowledge of an idiosyncratic construction casts doubt on the view that early acquisition requires innate linguistic knowledge.

In order to examine whether children adjust their phonetic speech categories, children of two age groups, five-year-olds and eight-year-olds, were exposed to a video of a face saying /aba/ or /ada/ accompanied by an auditory ambiguous speech sound halfway between /b/ and /d/. The effect of exposure to these audiovisual stimuli was measured on subsequently delivered auditory-only speech identification trials. Results were compared to a control condition in which the audiovisual exposure stimuli contained non-ambiguous and congruent sounds /aba/ or /ada/. The older children learned to categorize the initially ambiguous speech sound in accord with the previously seen lip-read information (i.e. recalibration), but this was not the case for the younger age group. Moreover, all children displayed a tendency to report the stimulus that they were exposed to during the exposure phase. Methodological improvements for adjusting such a response bias are discussed.

The aim of this study was to uncover factors accounting for the ability of children with specific language impairment (SLI) to learn agreement morphemes in intervention. Twenty-five children with SLI who participated in a six-month intervention program focused on teaching third person singular -s or auxiliary is/are/was showed a wide range of use of the target morpheme after intervention. Regression analyses showed that age and two factors expected to be related to agreement – the use of noun plural -s and subject/verb constructions prior to intervention – significantly predicted progress in the acquisition of agreement morphemes. In contrast, the pretreatment use of morphemes hypothesized to be unrelated to agreement was not a significant predictor of progress. The results indicate that the ability of children with SLI to learn agreement morphemes relies on their prior ability to use noun plural and subject/verb constructions.

How might syntactic bootstrapping apply in Turkish, which employs inflectional morphology to indicate grammatical relations and allows argument ellipsis? We investigated whether Turkish speakers interpret constructions differently depending on the number of NPs in the sentence, the presence of accusative case marking and the causative morpheme. Data were collected from 60 child speakers and 16 adults. In an adaptation of Naigles, Gleitman & Gleitman (1993), the participants acted out sentences (6 transitive and 6 intransitive verbs in four different frames). The enactments were coded for causativity. Causative enactments increased in two-argument frames and decreased in one-argument frames, albeit to a lesser extent than previously found in English. This effect was generally stronger in children than in adults. Causative enactments increased when the accusative case marker was present. The causative morpheme yielded no increase in causative enactments. These findings highlight roles for morphological and syntactic cues in verb learning by Turkish children.

This paper investigates the development of relative clauses in the speech of one German-speaking child aged 2 ; 0 to 5 ; 0. The earliest relative clauses we found in the data occur in topicalization constructions that are only a little different from simple sentences: they contain a single proposition, express the actor prior to other participants, assert new information and often occur with main-clause word order. In the course of the development, more complex relative constructions emerge, in which the relative clause is embedded in a fully-fledged main clause. We argue that German relative clauses develop in an incremental fashion from simple non-embedded sentences that gradually evolve into complex sentence constructions.

Young children learning English are biased to attend to the shape of solid rigid objects when learning novel names. This study seeks further understanding of the processes that support this behavior by examining a previous finding that three-year-old children are also biased to generalize novel names for objects made from deformable materials by shape, even after the materials are made salient. In two experiments, we examined the noun generalizations of 72 two-, three- and four-year-old children with rigid and deformable stimuli. Data reveal that three-year-old, but not two- or four-year-old, children generalize names for deformable things by shape, and that this behavior is not due to the syntactic context of the task. We suggest this behavior is an overgeneralization of three-year-old children's knowledge of how rigid things are named and discuss the implications of this finding for a developmental account of the origins of the shape bias.

The Agreement/Tense Omission Model (ATOM) predicts that English-speaking children will show similar patterns of provision across different tense-marking morphemes (Rice, Wexler & Hershberger, 1998). The aim of the present study was to test this prediction by examining provision rates for third person singular present tense and first and third person singular forms of copula BE and auxiliary BE in longitudinal data from eleven English-speaking children between the ages of 1 ; 10 and 3 ; 0. The results show, first, that there were systematic differences in the provision rates of the different morphemes; second, that there were systematic differences in the rate at which all of the three morphemes were provided with pronominal and lexical subjects; and, third, that there were systematic differences in the rate at which copula BE and auxiliary BE were provided with the third person singular pronominal subjects It and He and the first person singular subject pronoun I. These results replicate those of Wilson (2003), while controlling for some possible objections to Wilson's analysis. They thus provide further evidence against the generativist view that children's rates of provision of different tense-marking morphemes are determined by a single underlying factor, and are consistent with the constructivist view that children's rates of provision reflect the gradual accumulation of knowledge about tense marking, with much of children's early knowledge being embedded in lexically specific constructions.

Oral language skills in the preschool years are predictive of children's later reading success and literacy acquisition, and among these language skills, vocabulary and narrative ability play important roles. Children from low socioeconomic families face risks to their language development and because of threats to these skills it is important to identify factors that promote their development among high-risk groups. This preliminary study explored two potential factors that may be related to language skills in 56 low SES mother–child dyads (children aged 2 ; 8–4 ; 10), namely child temperament and parenting stress. Results showed that child temperament and parenting stress were related to children's oral language skills. Child temperament characteristics that would likely aid social interaction were related to narrative ability and children rated high on emotionality had poorer receptive vocabulary skills. Parenting stress was related to children's receptive and expressive vocabulary skills. Results are interpreted in terms of the possible mediating role of parent–child interactions in children's oral language skill development, and future directions for family intervention are discussed.

Segmental distributions of Korean infant-directed speech (IDS) and adult-directed speech (ADS) were compared. Significant differences were found in both consonant and vowel patterns. Korean-speaking mothers using IDS displayed more frequent labial consonantal place and less frequent coronal and glottal place and fricative manner. They showed more use of mid and low central vowels in IDS as well as more use of language-specific Korean phonemes. Mothers produced significantly more fortis and geminate and less lenis consonant phonemes in IDS than in ADS. Findings suggest that Korean mothers speaking to infants in the IDS speech style use sounds that more closely match infant production propensities as well as highlighting perceptually salient properties. IDS may serve to facilitate infant learning of ambient language phonological regularities.

Early language comprehension may be one of the most important predictors of developmental risk. The need for performance-based assessment is predicated on limitations identified in the exclusive use of parent report and on the need for a performance measure with which to assess the convergent validity of parent report of comprehension. Child performance data require the development of procedures to facilitate infant attention and compliance. Forty infants (20 at 1 ; 4 and 20 at 1 ; 8) acquiring English completed a standard picture book task and the same task was administered on a touch-sensitive screen. The computerized task significantly improved task attention, compliance and performance. Reliability was high, indicating that infants were not responding randomly. Convergent validity with parent report and 4-month stability was substantial. Preliminary data extending this approach to Mexican-Spanish are presented. Results are discussed in terms of the promise of this technique for clinical and research settings and the potential influences of cultural factors on performance.

Repetition is used for a range of functions in conversation. In this study, we examined all the repetitions used in spontaneous conversations by 41 French adult–child dyads, with children aged 2 ; 3 and 3 ; 6, to test the hypotheses that adults repeat to establish that they have understood, and that children repeat to ratify what adults have said. Analysis of 978 exchanges containing repetitions showed that adults use them to check on intentions and to correct errors, while children use them to ratify what the adult said. With younger children, adults combine their repeats with new information. Children then re-repeat the form originally targeted by the adult. With older children, adults check on intentions but less frequently, and only occasionally check on forms. Older children also re-repeat in the third turn but, like adults, add further information. For both adults and children, repeats signal attention to the other's utterances, and place the information repeated in common ground.

Evidentials are grammatical source-of-knowledge markers. In Bulgarian they provide information about authorship – whether the speaker has personally acquired the information or not – and modality – whether perceptual or cognitive mechanisms were involved in the information's generation. In two experiments, Bulgarian kindergarteners and third-graders (ages 6 and 9, N=96) had to decide which one of two utterances containing different evidentials to believe. Experiment 1 showed that children draw on modality information in their decisions: Third-graders favored perceptual over cognitive and kindergartners cognitive over perceptual sources. Experiment 2 showed that third-graders can also draw on the authorship information carried by evidentials: they favored first- over second-hand information. The discussion focuses on understanding the development of children's use of evidentials.