The ability to justify one's beliefs or actions requires linguistic, social, and cognitive skills, including an understanding of the psychological states of others and the negotiation of a socially-sensitive discourse. The production of verbal justifications was examined both quantitatively and qualitatively in eight pairs of eight- to eleven-year-old children whose natural discourse was videotaped, transcribed and coded for justifications. Previous research has frequently studied justifications in conflicts; children in this study produced most of their justifications both in the context of elaborating on a previously asserted claim and in conflicts. The statement justified and the justifications themselves most frequently focused on facts, evaluations, actions, and habitual characteristics or occurrences. A majority of the justifications were produced to support a statement which had some negative valence to it. Although causal connectives have previously been often used as the means for determining justifications, the children in this study rarely used causal connectives and mental verbs in statements with justifications. A qualitative analysis of the discourse of the dyads revealed differences in conversational styles which produced very different types of justifications. Some dyads made frequent use of narratives and co-constructed justifications; other dyads generally produced very short, often isolated justifications.

MacWhinney is to be commended for reopening questions about the logical problem of language acquisition in the light of new data and models. Unfortunately his discussion is marred by technical errors, false dichotomies, and inadequate attention to detail.

Children's ability to distinguish between the text, WHAT WAS SAID, and the intentional structure, WHAT WAS MEANT, was interrogated by means of verbatim and paraphrase questions in two types of discourse, narratives and nursery rhymes. Three- to seven-year-olds participated (n = 119, mean age 5·1). There was an interaction between the type of discourse and the younger children's ability to separate wording from intentional structure. In the narrative form they had difficulty rejecting true paraphrases when asked to focus on wording, while in the nursery rhyme form the difficulty was accepting a true paraphrase when asked to focus on intention.

This article uses longitudinal data from four Mexican-American children to explore two aspects of the acquisition of Spanish word stress that precede and accompany learning of the stress system itself. First, contrary to Allen & Hawkins' proposed universal ‘trochaic bias’ (Allen 1982, Allen & Hawkins 1977, 1979, 1980), it is shown that children have a ‘neutral start’ in stress learning: they approach the task of stress learning unbiased towards any particular stress type. Secondly, several examples are found in which children's attention to phonetic or semantic aspects of normatively unstressed syllables leads them to shift stress to that syllable.

In a conversation, adults expect speakers to be consistent in their use of a particular expression. We examine whether four-year-olds expect speakers to use consistent referential descriptions and whether these expectations are partner-specific. Using an eye-tracking paradigm, we presented four-year-olds with arrays of objects on a screen. During training, Experimenter 1 (E1) used a target expression to identify one object (i.e. “the spotted dog” to identify a dog that is both spotted and fluffy). Following training, either E1 or a new conversational partner (E2) presented children with test trials. Here, the target objects were referred to using either the original expression (e.g. “the spotted dog”) or a new expression (e.g. “the fluffy dog”). Eye-movements indicated that preschoolers were quicker to identify the target referent when the original expression was used by the same speaker. This suggests that four-year-olds, like adults, expect communicative partners to adhere to referential pacts.

The view that grammatical relations have substantial essence, designated as ‘subject’ or ‘object’ has difficulty in accounting for the variety of naturally acquirable grammatical relations. The acquisition of grammatical relations is examined from a theoretical framework, ROLE AND REFERENCE GRAMMAR, in which grammatical relations are decomposed into two separate types of structure: logical (semantic) structure and information (pragmatic) structure. The acquisition of grammatical relations from four languages is compared: (1) the definite accusative suffix and pragmatically motivated word order of Turkish; (2) Kaluli verb agreement, case and focus marking postpositions, and pragmatically motivated word order; (3) Hungarian definite and indefinite verb conjunction; and (4) Italian participial agreement and anaphoric, accusative case pronouns. Two conditions on structures are found to cause difficulty: the neutralization of a semantic or pragmatic distinction by interfering structures (e.g. Kaluli and Italian), and global case marking which forces the child to discover relevant semantic characteristics of both the actor and the undergoer (e.g. Hungarian and Kaluli). Structures that encode semantic or pragmatic distinctions independently are more easily acquired (e.g. Turkish). Piecing together discrete structures in a mosaic fashion, the child can acquire the great variety of grammatical relations that exist in human languages.

Recent attempts to classify the meanings of two-word utterances expressed by young children have assumed that children always intend ONE of the meanings adults might express. This paper challenges that assumption for two reasons. Firstly, it is by no means self-evidently true. Indeed, since children and adults conceptualize the world differently, they may also differ in what they choose to say about the world. Secondly, it has supported research strategies which are at best unjustified and at worst ambiguous. In fact, research based on the assumption that children always intend a meaning adults might express has provided interesting insights into the interpretations adults place upon children's utterances but said next to nothing about the meaning of these utterances. This paper concludes by suggesting an alternative approach to the latter problem.

Coordinate conjunction was evaluated in early child language with regard to its structural properties. In a series of four studies, 60 two- and three-year-olds grouped by MLU were studied in an elicited imitation task where in the linguistic form of sentences was varied according to conjunction structure (whether sentential or phrasal) and according to pattern of redundancy deletion in conjunction reduction (whether forward or backward in directionality). Both factors were found to affect children's imitation. The results suggested specific constraints on the structure of coordination in child language.

The interaction between lexical acquisition and acquisition of initial voiceless stops was studied in two normally developing children, aged 1;9 and 1;10, by acoustically examining the token-by-token accuracy of initial voiceless stop targets in different lexical items. Production accuracy was also examined as it related to the frequency of usage of different words, as well as the time when they entered the children's lexicons. Fewer than half of the words in the children's lexicons had tokens representing the emergence of accurate voiceless stop production prior to the session at which the voicing contrast was achieved. These words were primarily ‘old’ words that had been in the children's lexicons from the beginning of data collection, as opposed to ‘new’ words, first produced in later recording sessions. Findings are discussed in reference to the ‘lexical diffusion’ model of sound change and within the framework of nonlinear underspecification theory.

One of the most popular and widely used parent report instruments for assessing early language acquisition is the MacArthur-Bates Communicative Development Inventories (MB-CDI). This study compares normative data of the Italian Words and Sentences complete form (WS-CF) and short form (WS-SF). The samples included 752 children for the WS-CF and 816 children for the WS-SF designed for children aged 18–36 months. The concordance between WS-SF and WS-CF is analyzed in a subgroup of 65 children. The results revealed strong correlations between WS-CF and WS-SF in both lexical and grammar skills as well as strong relationship between lexical and grammar skills. There was a high percentage agreement (97%) between the two forms for scores below the 10th percentile, suggesting that the two forms may be used interchangeably in order to describe vocabulary and grammatical development.

In this paper the order in which wh-questions are acquired in the production and comprehension of two Korean children, aged 1;8–2;8 and 1;10–2; 10, is analysed and compared with the available crosslinguistic data. Consistencies in acquisition order are hypothesized to be based on universals of cognitive development, which constrain the comprehension and production of wh-forms and influence the order in which mothers introduce them, and on functionally based similarities in the input of form/function pairs across children and languages. Discrepancies in acquisition order are attributed to differences in interactive style across caregivers and children, leading to different input frequencies of particular forms and individual children's selection of different forms for use.

An empirical puzzle regarding toddlers' fast mapping motivated the current investigation. Whereas children between 1;10 and 2;1 have shown only a modest rate of mapping novel nouns onto unfamiliar rather than familiar objects, a very high rate has been observed in those between 1;4 and 1;8 (Mervis & Bertrand, 1994). Study 1 examined whether young two-year-olds (N=40, mean age=2;1) might map at a higher rate when tested with procedures unique to Mervis & Bertrand's assessment – strong corrective feedback rather than mild positive non-contingent feedback; large sets of test objects rather than pairs; presentation of easier tests first. Only the first variable affected performance in a manner that could solve the puzzle. Unfamiliar kinds were selected at a much higher rate under corrective (0·86) than non-contingent (0·57) feedback. Although nearly every child in the non-contingent group chose correctly on the first trial, many failed to do so thereafter. In Study 2, rather than presenting a test word to the children (N=16, mean age=2;2), the experimenter merely asked for ‘the one I want’. Unfamiliar kinds were selected much less often than in Study 1, suggesting that at least one lexical principle proposed in the literature underlies the noun mapping preference. Changes over trials in the two studies indicated that the noun mapping preference is quite prevalent, but unless initial choices are strongly reinforced, an increase in the salience of familiar kinds after the first trial lures some children into error. Consistent with this analysis, toddlers in Study 3 (N=24, mean age=2;1) who received non-contingent strong acceptance for their noun mapping decisions, selected unfamiliar kinds more often than those who had received non-contingent mild acceptance in Study 1.

The present study examined the number-specific parental language input to Mandarin- and English-speaking preschool-aged children. Mandarin and English transcripts from the CHILDES database were examined for amount of numeric speech, specific types of numeric speech and syntactic frames in which numeric speech appeared. The results showed that Mandarin-speaking parents talked about number more frequently than English-speaking parents. Further, the ways in which parents talked about number terms in the two languages was more supportive of a cardinal interpretation in Mandarin than in English. We discuss these results in terms of their implications for numerical understanding and later mathematical performance.

Socio-economic status (SES) impacts the amount and type of input children hear in ways that have developmental consequences. Here, we examine the effect of SES on the use of variation sets (successive utterances with partial self-repetitions) in child-directed speech (CDS). Variation sets have been found to facilitate language learning, but have been studied only in higher-SES groups. Here, we examine their use in naturalistic speech in two languages (Hebrew and English) for both low- and high-SES caregivers. We find that variation sets are more frequent in the input of high-SES caregivers in both languages, indicating that SES also impacts structural properties of CDS.

Early spontaneous gesture, specifically deictic gesture, predicts subsequent vocabulary development in typically developing (TD) children. Here, we ask whether deictic gesture plays a similar role in predicting later vocabulary size in children with Down Syndrome (DS), who have been shown to have difficulties in speech production, but strengths in spontaneous gesture and baby sign use. We compared the gestures and baby signs produced by twenty-three children with DS (Mage = 2;6) and twenty-three TD children (Mage = 1;6), in relation to their expressive spoken vocabulary size one year later. Children with DS showed significant deficits in gesture production, particularly for deictic gestures, but strengths in baby sign production, compared to their typically developing peers. More importantly, it was the baby signs produced by children with DS, but not deictic gestures, that predicted their spoken vocabulary size one year later. Our results further highlight the important role baby signs can play in language development in children with developmental disorders.

Twenty-month-old children learned to recognize nonsense labels for five novel object concepts and were tested on generalization to variants of these concepts. Children were presented with either one or three examples of each object type during learning sessions. Results showed that receptive learning of names for object concepts was significantly related to a number of possible manipulations specific to each object type and to labelling by children. Children's generalization choices were consistent with adults' ranking of similarity of variants to concept prototypes. Children who learned less well were more likely to generalize to new instances of an object concept and to a greater number of variants if they had been exposed to three rather than one example during training sessions. Results also support the hypothesis that differentiation of objects in interaction is important to the formation of an object concept at this age.

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 goal of the present study was to examine if internationally adopted (IA) children from China (M = 10;8) adopted by French-speaking families exhibit lags in verbal memory in addition to lags in verbal abilities documented in previous studies (Gauthier & Genesee, 2011). Tests assessing verbal and non-verbal memory, language, non-verbal cognitive ability, and socio-emotional development were administered to thirty adoptees. Their results were compared to those of thirty non-adopted monolingual French-speaking children matched on age, gender, and socioeconomic status. The IA children scored significantly lower than the controls on language, verbal short-term memory, verbal working memory, and verbal long-term memory. No group differences were found on non-verbal memory, non-verbal cognitive ability, and socio-emotional development, suggesting language-specific difficulties. Despite extended exposure to French, adoptees may experience language difficulties due to limitations in verbal memory, possibly as a result of their delayed exposure to that language and/or attrition of the birth language.

Specific relationships between verbal and nonverbal aspects of caregiver attention-focusing events and later verbal IQ were investigated for a risk sample of 26 very low birthweight [VLBW], preterm [PT] children. Videotaped interactions between VLBW, PT children at 2;0 and their caregivers were coded for caregiver attention-focusing speech and/or caregiver attention-focusing gestures (display, demonstration and pointing), caregiver gesture–speech combinations, and for child attention-sharing through gesture and social gaze. To investigate the specific effects of caregiver and child interactional factors, analyses statistically controlled for cognitive status. Simultaneous multiple regression analyses found that overall caregiver attention-focusing involving gesture, child attention-sharing behaviours, and cognitive status each significantly and uniquely contributed to verbal IQ at 3;0. Further analyses contrasted the contributions of caregiver gesture with relevant descriptive speech, caregiver gesture with no speech/nondescriptive speech, and caregiver pointing. Results of these analyses suggest that caregiver gesture with relevant descriptive speech makes a unique and positive contribution to later language performance.