Many theorists have dismissed a priori the idea that distributional information could play a significant role in syntactic category acquisition. We demonstrate empirically that such information provides a powerful cue to syntactic category membership, which can be exploited by a variety of simple, psychologically plausible mechanisms. We present a range of results using a large corpus of child-directed speech and explore their psychological implications. While our results show that a considerable amount of information concerning the syntac-tic categories can be obtained from distributional information alone, we stress that many other sources of information may also be potential contributors to the identification of syntactic classes. I.

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“Origins of communicative disorders ” to Elizabeth Bates, and by a grant from the John D. and Catherine T. MacArthur Foundation. We are grateful to Larry Juarez and Meiti Opie The effects of focal brain injury are investigated in the first stages of language development, during the passage from first words to grammar. Parent report and/or free speech data are reported for 53 infants and preschool children between 10- 44 months of age. All children had suffered a single, unilateral brain injury to the left or right hemisphere, incurred before six months of age (usually in the pre- or perinatal period). This is the period in which we should expect to see maximal plasticity, but it is also the period in which the initial specializations of particular cortical regions ought to be most evident. In direct contradiction of hypotheses based on the adult aphasia literature, results from 10- 17 months suggest that children with righthemisphere injuries are at greater risk for delays in word comprehension, and in the gestures that normally precede and accompany language onset. Although there were no differences between left- vs. right-hemisphere injury per se on expressive language, children whose lesions include the left temporal lobe did show significantly greater delays in expressive vocabulary and

Cross-linguistic similarities and differences in early lexical and grammatical development are reported for 1001 English-speaking children and 386 Italian-speaking children between 1;6 and 2;6. Parents completed the English or Italian versions of the MacArthur Communicative Development Inventory: Words and Sentences, a parent report instrument that provides information about vocabulary size, vocabulary composition and grammatical complexity across this age range. The onset and subsequent growth of nouns, predicates, function words and social terms proved to be quite similar in both languages. No support was found for the prediction that verbs would emerge earlier in Italian, although Italians did produce a higher proportion of social terms, and there were small but intriguing differences in the shape of the growth curve for grammatical function words. A strikingly similar nonlinear relationship between grammatical complexity and vocabulary size was observed in both languages, and examination of the order in which function words are acquired also yielded more similarities than differences. However, a comparison of the longest sentences reported for a subset of children demonstrates large cross-linguistic differences in the

Aphasia (defined as the loss or impairment of language abilities following acquired brain injury) is strongly associated with damage to the left hemisphere in adults. This well-known finding has led to the hypothesis that the left hemisphere is innately specialized for language, and may be the site of a specific "language organ". However, for over a century we have known that young children with left-hemisphere damage (LHD) do not suffer from aphasia, and in most studies do not differ significantly from children with right-hemisphere damage (RHD). This result provides strong evidence for plasticity, i.e., brain reorganization in response to experience, and constitutes a serious challenge to the language organ hypothesis. This chapter reviews the history of research on language outcomes in children vs. adults with unilateral brain injury, addressing some discrepancies in the literature to date, including methodological confounds that may be responsible for those discrepancies. It also reviews recent prospective studies of children with unilateral injury as they pass through the first stages of language development. Prospective studies have demonstrated specific correlations between lesion site and profiles of language delay, but they look quite different from lesionsymptom correlations in adults, and gradually disappear across the course of language development. The classic pattern of brain organization for language observed in normal adults may be the product rather than the cause of language learning, emerging out of regional biases in information processing that are relevant for language, but only indirectly related to language itself. If those

To explore early language acquisition in internationally adopted preschoolers, we collected parental reports (CDI-2) and speech samples from 14 children adopted from China between the ages of 2 years, 7 months and 5 years, 1 month. Their lexical and syntactic development was qualitatively similar to infants acquiring English as a first language: nouns and social words dominated early vocabularies; verbs and closed-class items became more frequent as vocabulary size increased; and lexical and syntactic development were tightly correlated. This research has several implications for clinicians. First, it demonstrates that parental reports provide valid information during the first year after adoption and could be useful in identifying preschool children in need of further assessment. Nine to 15 months after arrival many children reached the ceiling of the CDI-2, suggesting that this instrument has limited utility after the first year. Finally, the rapid lexical and syntactic growth of these children suggests that many of them may eventually catch up with their native-born peers.

Three exploratory studies were carried out to determine if there was continuity in the development of language in young children at the upper and lower extremes of the normal continuum, and if it was possible to use variables from an early assessment to predict their language status at a later date. Studies 1 and 2 examined continuity over 6-month period (from approximately 20 to 26 and 13 to 20 months of age, respectively); Study 3 examined continuity from 8 to 30 months of age. Results provided solid evidence for continuity at the group level but no evidence of ability to predict outcome for individual children using the vocabulary production, vocabulary comprehension, and gesture production variables included in this study. 2 Many parents wonder whether their child is normal. They wonder whether he or she is abnormally slow to develop, or so precocious that early celebration is warranted. During their child's first year of life, most parents worry about issues like sleeping, eating, and attainment of motor milestones (especially crawling and walking). During the second year, the focus switches to communication and language. This is true for physicians and other health care professionals

Feldman et al. criticize the MacArthur Communicative Development Inventories (CDIs) as having too much variability, too little stability, and insufficient ability to predict early language delay. We present data showing that these characteristics of the CDI are authentic reflections of individual differences in early language development rather than measurement deficiencies. We also respond to their critical assertions concerning sociodemographic influences on the CDI scores.

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