Some apparently normal children inexplicably have difficulty acquiring language. Specific language impairment (SLI) is the term for severe developmental delays in the production and/or comprehension of language that do not seem to be due to hearing loss, mental retardation, motor deficits, neurological or psychiatric disorders, or lack of exposure to language. In this project, three types of studies will be conducted on normally-developing and SLI children: 1) analyses of longitudinal spontaneous speech samples; 2) analyses of cross-sectional elicited speech samples; and 3) analyses of imitated sentences that systematically vary in phonological, syntactic and lexical complexity. Through careful analyses of these data, we will address the following questions:
* What is the nature of the linguistic deficit(s) in SLI? * To what extent are some components of language (e.g., syntax, phonology, lexicon) spared relative to others in SLI? * To what extent do performance factors play a role in SLI children's deficits? To what extent does SLI and normal children's performance on language tasks degrade as performance load increases? * Do SLI and normal children have a single (limited) pool of performance resources for all language tasks, or does each subcomponent of language have its own dedicated resources? Does increased performance load in one area of language lead to decreased performance in just that area or in other areas of language as well?
