Prior empirical work in semantic development has produced an impressive finding showing that children can reliably detect a modal's relative force (e.g. that must is stronger sounding than may) by five-and-a-half years of age. We investigate the extent to which a representation of relative force can account for an understanding of epistemic modals when their logical meaning is considered (i.e. when modals are interpretable as expressions of necessary and possible conclusions). Experiment 1 presents a replication of Hirst & Weil's hidden-object task, which originally included the supremely forceful indicative is. Thirty-two five-year-olds were required to find a peanut hidden under one of two containers based on a pair of statements that contrasted is with has to, has to with might, or is with might. Half the children were entitled to search for the peanut upon hearing the two statements and half were required to indicate only where they would look. Results largely confirmed the influence of relative force in this paradigm. Both groups of children usually searched under the container associated with the stronger-sounding term. Experiment 2 employed a modified version of the hidden-object task in which contrasts presented one true and one false modal statement and 32 five-year-olds, 20 seven-year-olds, 16 nine-year-olds and 20 adults were asked to determine which of two statements was correct. Half the contrasts presented a relatively weaker-sounding modal term in the true statement and the other half presented equally forceful modal terms in the two statements. No age group systematically endorsed a false stronger-sounding modal statement over a true weaker-sounding one. The five-year-olds' rate of correct responding overall was above levels predicted by chance. Mature logical modal understanding was found among seven-year-olds who routinely endorsed a contrast's true modal statement. These findings suggest that deductive inference is an early semantic component of modal terms.

Case studies are presented for two linguistically precocious children (early-talkers) aged 1;9 and 1;5, one of whom represents a striking dissociation between vocabulary size and mean length of utterance. Each early-talker is compared to controls in the same language stage; 10 in Early Stage I (mean age 1; 7) and 10 in Stage II (mean age 2; 3). Data are explored to determine if the dissociation is best characterized as one between grammar and semantics, or a difference in cognitive style. Results showed that the child who used mostly single words produced high proportions of predicates and bound and closed class grammatical morphemes, providing no evidence of a dissociation between grammar and semantics. Results also failed to support a clear contrast between analytic and holistic processing, although partial support was found for some predictions based on cognitive style. A unifying account is proposed that considers differences in auditory short term memory, a factor which could affect the size of the linguistic unit that children can store, manipulate, and/or retrieve at a particular point in development.

It is commonly believed that colour terms are acquired unusually slowly. However, several recent studies suggest that preschoolers have more colour term knowledge than previously believed. In two studies, we investigated the colour term knowledge of 49 two-year-olds and the influence of schooling on their colour term acquisition. Both studies revealed considerable knowledge in such young children. A longitudinal comparison of children with and without school experience in Study 2 indicated that the higher performance of the school group could not be accounted for by differences predating that group's experience. In reviewing the evidence from the children's performance, we conclude that contemporary children's early and frequent experience with colour terms may account for this cohort's improved performance over previous generations of children.

This study explores the communicative use of the gestural and vocal modalities by normally developing Italian children during the transition from one- to two-word speech. We analysed the spontaneous production of 12 children at 1;4 and at 1;8, focusing on the use of two-element combinations of words and/or gestures. Results indicated that use of gesture and gesture-word combinations during the transition to two-word speech is a robust feature of communicative development across a relatively large number of children in a rich gestural culture, and that the number of gesture-word and two-word combinations increased significantly from 1;4 to 1;8. Number of gestures and gesture-word combinations produced at 1;4 was also predictive of total vocal production at 1;8. Findings are discussed in terms of the role of gesture as a transitional device en route to two-word speech.

Global tendencies for the relative absence of covocalization (simul- taneous talk) have been identified in both conversations between adult partners and conversations between mothers and their infants; in each case, the alternating mode in which one partner speaks at a time is predominant. The present investigation examined the timing of the partners' talk in mother-infant engagements over infant age to determine whether: (a) variations occur in the incidence of the alternating mode; and (b) variations occur in the extent to which the alternating mode predominates. Conversations involving a total of 48 mothers and their infants aged from 0;3 to 2;0 were investigated at each of eight infant ages (0;3, 0;6, 0;9, 1;0, 153, 1;6, 1;9 and 2;0). The results indicated that, within a global tendency for the relative absence of covocalization, there was: (a) a curvilinear tendency for the incidence of covocalization to decrease over the first 18 months, and then to increase; and (b) a linear tendency for the extent to which the alternating mode predominates to increase over age. These changes are interpreted as reflecting the facilitative effects of covocalization in the case of young preverbal infants, and the need for the alternating, turn-taking pattern to predominate as mutual comprehension becomes possible in conversations between mothers and their older infants.

There has been a growing trend in recent years towards the attribution of adult-like syntactic categories to young language-learning children. This is based, at least in part, on studies which claim to have found positive evidence for syntactic phrase structure categories in young children's speech. However, these claims contradict the findings of previous research which suggest that the categories underlying children's early multi-word speech are much more limited in scope. The present study represents an attempt to reconcile the findings of these different lines of research by focusing specifically on Valian's (1986) criteria for attributing the syntactic category of determiner to young children. The aim is, firstly, to replicate Valian's results regarding her determiner criteria on a new sample of seven children between the ages of 1;20 and 2;6; secondly, to investigate the extent to which children show overlap in the contexts in which they use different determiner types; and, thirdly, to compare this with a controlled measure of the overlap shown by competent adult speakers. The results suggest that Valian's criteria for attributing a syntactic determiner category are too generous and could be passed by children with a relatively small amount of limited scope knowledge. They also provide at least some evidence that a limited scope formula account of children's early determiner use may fit the data better than an adult-like syntactic account.

If the logic of natural language negation were classical – a simple matter of true and false – then it would be a disaster to answer a question like Is this essay good? with Yes and no. The overwhelming majority of adults (N = 40) asked to resolve this apparent contradiction were found to do so by appealing to the structure of the essay (e.g. Its thesis was good but its argument was not). Three-year-olds (N = 24), when suitably prepared, also appealed to object structure to resolve a similar apparent contradiction. These results are discussed in relation to a non-classical logical model that can handle object structure.

Research on early mother-child interaction has documented the crucial role affect plays in the content and modulation of early interactions. For hearing mothers, voice quality is considered to be the single most informative channel for affective expression. For deaf caregivers who use American Sign Language (ASL), the vocal channel is unavailable, and facial expression is critically important. Not only do facial behaviours signal affective and communicative information, but specific facial behaviours also function as obligatory grammatical markers. This multifunctionality of facial expression presents a dilemma for deaf parents signing to their toddlers as these two systems potentially compete for expression on the face. This study addresses how affective facial expression interacts with the linguistic forms in ASL motherese. To address this issue, we present data from both cross-sectional and longitudinal videotaped interaction from a total of 15 deaf mothers signing with their deaf toddlers (ages 0;9–2;8). Using Ekman & Friesen's Facial Action Coding System (FACS) (1978) we analysed child-directed maternal wh- questions. Because they are frequent in early discourse, AND they require furrowed brows which also signal anger and puzzlement, wh- questions represent an ideal context to address the potential conflict of grammatical and affective facial expression in ASL motherese. Our studies indicate a shift from affect to grammar at about the child's second birthday. These findings shed new insight on the nature and possible role of input on the language acquisition process.

Distinctive feature specification and representation in phonological acquisition are examined in the context of underspecification theory. Subjects were 30 children (aged 3;1 to 5;10) who exhibited systematic differences in their linguistic knowledge of target phonological contrasts. A free classification task was used to tap children's conceptual knowledge of these contrasts, with features of place and manner experimentally manipulated. Three questions were addressed: which features do children use to categorize segmentai information, do the defining features of a category shift as the phonological system advances, and which framework of underspecification theory best accounts for the results? All children categorized segments on the basis of marked nonredundant featural properties, and used only one feature value to define category membership consistent with radical underspecification. Linguistic knowledge and linguistic input both influenced children's category judgements, but to different degrees. The emergence of phonological categories involved increasing feature differentiation as the child's productive phonology advanced.

This study investigates how children of different ages talk about a conversation that they have witnessed. 48 Turkish children, five, nine and thirteen years in age, saw a televised dialogue between two Sesame Street characters (Bert and Ernie). Afterward, they narrated what they had seen and heard. Their reports were analysed for the development of linguistic devices used to orient their listeners to the relevant properties of a conversational exchange. Each utterance in the child's narrative was analysed as to its conversational role: (1) whether the child used direct or indirect quotation frames; (2) whether the child marked the boundaries of conversational turns using speakers' names and (3) whether the child used a marker for pairing of utterances made by different speakers (agreement-disagreement, request-refusal, questioning-answering). Within pairings, children's use of (a) the temporal and evaluative connectivity markers and (b) the kind of verb of saying were identified. The data indicate that there is a developmental change in children's ability to use appropriate linguistic means to orient their listeners to the different properties of a conversation. The development and use of these linguistic means enable the child to establish different social roles in a narrative interaction. The findings are interpreted in terms of the child's social-communicative development from being a ‘character’ to becoming a ‘narrator’ and ‘author’ of the reported conversation in the narrative situation.

Twenty-one videotape recorded interactions of 42 preschool children (aged 3;4 to 5;3) in same-sexed dyads were coded and analysed to see how these children used the word no in their interactions. Results showed that while boys and girls used the word no equally frequently, they were found to use the word in different ways. A trend for boys to use no when correcting or prohibiting their playmate's behaviour more often than girls was revealed. Girls were more likely to provide reasons for denying or rejecting their playmate's proposition or suggestion. The overall findings of this study are comparable to previously reported results indicating that males and females employ different styles of speech in order to accomplish the same goal. However, unlike most studies conducted on language and sex, this study offers a unique approach in that it examines how boys and girls use a word that occurs equally frequently in their vocabulary to accomplish different goals.

We reply to Mervis & Bertrand's report of three children (aged 1; 6–1; 8 at the start of the study) who evidenced a ‘late’ vocabulary spurt. Differences in assessing productive vocabulary, and the questionable inference that size of the lexicon is a reliable indicator of the vocabulary spurt, make it inappropriate to compare these children to previous studies that directly measure change in rate of word learning. Further work using continuous records of lexical development and controls for repeated cognitive assessments is needed to test hypotheses about the spurt and related cognitive and linguistic achievements.

The properties of reflexives vary across adult languages with respect to (i) the domain in which a reflexive may be bound and (ii) the syntactic positions an appropriate antecedent may occupy. These two issues have been approached in GB theory in various ways, each with specific implications for acquisition. In this paper we examine these implications by testing normal and Specific Language Impaired (SLI) children for evidence of the binding domain and orientation properties of their grammars. The investigation reveals that, contrary to most previous claims, normal children acquiring English pass through a long-distance binding stage. SLI children, however, do not display this pattern, tending instead to behave like very young normal children in requiring the nearest available NP to be the antecedent. We argue that this constitutes an early binding stage not previously identified. Finally, we interpret our findings in terms of a conception of acquisition dubbed the ‘competing grammars’ model, according to which competing incompatible grammars may coexist in the mind of the learner.

In this study we investigate the re-introduction of referents in the Frog stories told by Italian children aged 4–10 (N = 100). We found that for every age group full nouns are the most frequent forms used for reference re-introduction. Null forms, such as clitic pronouns or person/number inflection on the verb, are the second most frequent forms. A detailed analysis of null forms shows that children of different ages exploit different properties of the verbal and non-verbal context which can make a referent predictable. Compared to preschoolers, elementary school children are more likely to use null forms when the semantic content of the verb, or the structure of the preceding text make referents inferrable. On the other hand, preschoolers tend to exploit the importance of a character in the story plot, or the visual availability of the referent in the non-verbal context, as properties that make an entity salient enough to prevent the speaker from using overt linguistic forms such as full nouns. Our study confirms results of previous research, showing that elementary school children are more competent than preschoolers in integrating the semantic content of the current utterance into the context generated by previous discourse.