The use of the mutual exclusivity constraint was examined in three-year-old and six-year-old children who were either monolingual in English (N=32) or bilingual in English/Urdu (N=32) or in English/Greek (N=32). Three tests of the constraint were used: disambiguation, rejection, and restriction. On the disambiguation test, the mutual exclusivity bias was significantly more evident in five- and six-year-old monolingual children than in their same-age bilingual peers. Monolingual children were also more likely than bilingual children to reject a new name for a familiar object. However, using a restriction test, neither monolingual nor bilingual children readily accepted and restricted typical names for hybrid objects. Developmental differences were also found, as older (five- to six-year-old) monolingual children's responses on the tests were generally more consistent with the constraint than younger (three- to four-year-old) children's responses. Nevertheless, bilingual children did use the constraint, but not to the extent of monolingual children.

This paper explores the effects of certain aspects of verb input on verb acquisition. It has been observed that the timing of a verb model affects children's learning of the verb (Tomasello & Kruger, 1992). It has also been observed that the focus of the event to which the verb refers affects the argument structure children assign to the verb (Pinker, 1989). This experiment investigated the interaction between the timing of verb models and the focus of the events to which they refer. Thirty children aged from 2;3 to 3;6 heard two novel verbs, one movement focused and the other result focused. Half heard the verbs before the event (impending condition) and half after it (completed condition). An interaction of verb timing and verb focus was found. The movement verb was learned better in the impending condition and the result verb in the completed condition. The contribution of this finding to our understanding of the processes involved in verb acquisition is considered.

This study describes English-speaking children's acquisition of voice onset time (VOT), a segmental feature that specifies the timing of word-initial stop consonants, and final-syllable vowel lengthening (FSVL), a suprasegmental feature that influences the timing of vowels. The purpose of the study was to evaluate two hypotheses about the acquisition of speech timing contrasts: a ‘motoric’ hypothesis predicting that children would control the vowel duration contrast earlier than the consonantal one (FSVL before VOT), and a ‘representation’ hypothesis predicting that children would control the contrast represented on the segmental level of linguistic description earlier than the contrast represented on the suprasegmental level (VOT before FSVL). Longitudinal acquisition patterns for both contrasts were compared in ten children between the mean ages of 1;6 and 2;0. The results, indicating that English-speaking children usually acquired VOT before FSVL, are discussed in light of evidence that French-speaking children acquire analogous contrasts in the opposite sequence. The crosslanguage comparisons support limited forms of both the motoric and representation hypotheses. As promising topics for further study, the results also suggested the importance of individual differences, and the variability of timing features in the input.

Investigation of children's understanding of the cognitive verb forget has shown that young children do not consider the role of prior knowledge when using this verb. Thus, someone may be said to have forgotten a fact despite not ever having previously known it. However, forget can also be used to refer to a failure to recall a prior intention. Three experiments examined the role of prior intention as well as prior knowledge in the comprehension of forget by 160 young children aged four to eight years. The results showed that children initially have two interpretations of forget: as an unfulfilled desire rather than a failure to recall a prior intention, and as a state of not knowing rather than a failure to recall prior knowledge. Explanations for the late comprehension of forget are discussed in terms of representation of knowledge and intention, processing capacity and exposure to pragmatic usages.

The purpose of this research was to investigate the potential interaction of conceptual representations and linguistic systems in the process of language acquisition. Language–thought interactions were studied in 80 American, 48 Finnish and 48 Polish preschool children. The research focused on the conceptual and linguistic development of space and time. The spatial and temporal conceptual tasks were designed to measure the transition from experiential to inferential knowledge of space/time representations. In the linguistic domain, comprehension and production tests were used to evaluate the children's capacity to understand mono- and bi-referential location in space and time, where mono-referential location involves a single referent object/event with intrinsic properties (e.g. in/on or past/non-past), and bi-referential location requires two or more referent objects/events and relative perspective (e.g. deictic front/back or before/after). The conceptual and linguistic tests revealed significant changes during the period from two to five years of age, and measures of conceptual development were correlated with measures of linguistic development. As spatial and temporal representations became more structured, children were able to move from mono- to bi-referential location. In a comprehension test, we discovered an interaction of language by dimension. Finnish children found spatial distinctions relatively easy and Polish children found temporal distinctions relatively easy. This interaction was expected on the basis of the relative complexity of the morpho-syntactic coding in the spatial and temporal systems of the two languages. However, the argument relating the timing of acquisition to the transparency versus opacity of the linguistic systems was not supported by the English language comparison. Finally, the Finnish children were relatively better able to accomplish the spatial conceptual tasks as compared to the Polish children. This finding is consistent with a developmental concept of linguistic relativity. In general, the research indicates that spatial and temporal linguistic systems and representational knowledge interact during development with the influence occurring in both directions.

The present study was conducted to assess the effect of didactic techniques used during storybook reading on young children's acquisition of new vocabulary introduced in storybooks. Thirty children for each group of three- and four-year-old children were read one storybook individually. The study included three storybook reading conditions: single-reading, repeated-reading and questioning. In both the repeated-reading and the questioning conditions, the storybook was read three times. Children in the questioning condition were asked, during each reading of the storybook, to label target items with the novel words. Listening to multiple readings of a storybook facilitated children's acquisition of expressive and receptive vocabulary, whereas answering questions during the multiple readings was more helpful to the acquisition of expressive than receptive vocabulary. These findings suggest that, under certain conditions, didactic techniques used by adults have differential effects on preschoolers' receptive and expressive vocabulary.

Beliefs about whether or not children receive corrective input for grammatical errors depend crucially on how one defines the concept of correction. Arguably, previous conceptualizations do not provide a viable basis for empirical research (Gold, 1967; Brown & Hanlon, 1970; Hirsh-Pasek, Treiman & Schneiderman, 1984). Within the Contrast Theory of negative input, an alternative definition of negative evidence is offered, based on the idea that the unique discourse structure created in the juxtaposition of child error and adult correct form can reveal to the child the contrast, or conflict, between the two forms, and hence provide a basis for rejecting the erroneous form. A within-subjects experimental design was implemented for 36 children (mean age 5;0), in order to compare the immediate effects of negative evidence with those of positive input, on the acquisition of six novel irregular past tense forms. Children reproduced the correct irregular model more often, and persisted with fewer errors, following negative evidence rather than positive input.

Previous studies of children's comprehension of compound nouns show that three-year-olds can identify the appropriate referent for a compound when shown picture arrays that include salient distractors. The four studies presented here investigate comprehension of one kind of compound, metaphoric compounds (i.e. noun–noun compounds in which one noun expresses similarity to another object, as in catfish). Forty-four three-year-olds, 45 five-year-olds and 22 adults were shown a series of picture arrays and were asked to identify referents of various types of metaphoric compounds. The arrays included target pictures that had metaphoric resemblances based on shape (e.g. bug shaped like a stick) or on colour/pattern (e.g. shells with black and white stripes, like a zebra). Results showed that three- and five-year-olds can comprehend shape-based metaphoric compounds such as stick-bug, even when faced with salient distractors (e.g. a stick, a bug next to a stick). The younger children had some difficulty with colour-based compounds, such as zebra-shells. Overall, five-year-olds outperformed three-year-olds but performed significantly less well than adults. However, even at age 3, children did not show a general expectation to interpret the compounds literally.

Pine & Lieven (1993) suggest that a lexically-based positional analysis can account for the structure of a considerable proportion of children's early multiword corpora. The present study tests this claim on a second, larger sample of eleven children aged between 1;0 and 3;0 from a different social background, and extends the analysis to later in development. Results indicate that the positional analysis can account for a mean of 60% of all the children's multiword utterances and that the great majority of all other utterances are defined as frozen by the analysis. Alternative explanations of the data based on hypothesizing underlying syntactic or semantic relations are investigated through analyses of pronoun case marking and of verbs with prototypical agent–patient roles. Neither supports the view that the children's utterances are being produced on the basis of general underlying rules and categories. The implications of widespread distributional learning in early language development are discussed.

This paper provides a further investigation into the linguistic abilities of a subgroup of 12 Grammatical specific language impaired (SLI) children (aged 10;2 to 13;11). The study investigates the use of referential expressions (e.g. pronouns) in a narrative discourse, and provides insight into the underlying nature of Grammatical SLI, thereby contributing to the modularity debate. Previous investigations indicate that Grammatical SLI children have a deficit with dependent structural relationships, i.e. a Representational Deficit for Dependent Relationships (RDDR). Grammatical SLI children's RDDR appears to be a modular language deficit. To test this claim, linguistic representations of dependent structural relationships which are not part of the modular language system are investigated using a narrative discourse based on the picture book Frog where are you? The SLI children's pattern of referential expressions was compared with 36 language ability controls (aged 6;4 to 9;8). The findings indicated that the Grammatical SLI children have relatively mature linguistic development in the use of referential expressions to produce a cohesive, structured narrative discourse. The view of the organisation of the mind in which a modular language system can be differentially impaired from aspects of language which rely on the central system can most easily account for the data. Thus, the data support the hypothesized modular nature of Grammatical SLI children's underlying linguistic deficit. The implications of the findings for language acquisition are discussed.

This study investigated the general nature of conversational interaction in mother–twin–twin triads. Four sets of firstborn twins (2;3) were videotaped during 15 minutes of free play with their mothers. Analyses revealed that triadic conversations were approximately five times longer, and elicited more turns from all speakers, than dyadic conversations between a mother and a single twin. Twins also responded as often to comments and requests made to another person as to those directed to themselves, but responded more often to questions addressed directly to them than to others, indicating reliable monitoring of language not addressed to them. These results largely parallel those reported for mother–infant–sibling triads and indicate the unique effects of triadic exchanges are not due to the relative linguistic levels of the child partners.