ABSTRACT
This chapter explores language acquisition in a few different retardation syndromes, to address the kinds of questions that have been raised about the nature of language. The general picture of language acquisition across different populations of atypical children provides strong evidence for both important differences as well as similarities among children with various neuro-developmental disorders. The most striking findings are the contrasting profiles that are found between populations across domains of language. The chapter provides the detailed presentation of language acquisition in a number of different neuro-developmental disorders, including Down syndrome, Williams's syndrome, autism, and hydrocephalus. It illustrates some of the asynchronies which suggest that in different syndromes different mechanisms may be impaired. Thus in autism impairments are primarily to theory of mind mechanisms that play a role in language and communication, whereas in Down syndrome there are specific impairments in the computational mechanisms that underlie the processing of grammatical information.
