Publications

Abstract

This study investigates the role of performance limitations in children's early acquisition of verb-argument structure. Valian (1991) claims that intransitive frames are easier for children to produce early in development than transitive frames because they do not require a direct object argument. Children who understand this distinction are expected to produce a lower proportion of transitive verb utterances early in development in comparison with later stages of development and to omit direct objects much more frequently with mixed verbs (where direct objects are optional) than with transitive verbs. To test these claims, data from nine children aged between 1;10.7 and 2;0.25 matched with Valian's subjects on MLU were examined. When analysed in terms of abstract syntactic structures Valian's findings are supported. However, a detailed lexical analysis of the data suggests that the children were not selecting argument structure on the basis of syntactic complexity. Instead, a clear predictor of the frames used by the children with specific verbs was the frames used by the children's mothers with those same verbs, regardless of whether they were transitive or intransitive. This suggests that the most important determinant of the children's use of verb frame was the specific patterns of verb use in the input rather than abstract grammatical knowledge constrained by performance limitations. The implications of these findings for performance-based explanations for children's early errors and early patterns of language use are discussed.

Abstract

Observational and checklist measures of vocabulary composition have both recently been used to look at the absolute proportion of nouns in children's early vocabularies. However, they have tended to generate rather different results. The present study is an attempt to investigate the relationship between such measures in a sample of 26 children between 1;1 and 2;1 at approximately 50 and 100 words. The results show that although observational and checklist measures are significantly correlated, there are also systematic quantitative differences between them which seem to reflect a combination of checklist, maternal-report and observational sampling biases. This suggests that, although both kinds of measure may represent good indices of differences in vocabulary size and composition across children and hence be useful as dependent variables in correlational research, neither may be ideal for estimating the absolute proportion of nouns in children's vocabularies. The implication is that questions which rely on information about the absolute proportion of particular kinds of words in children's vocabularies can only be properly addressed by detailed longitudinal studies in which an attempt is made to collect more comprehensive vocabulary records for individual children.