ABSTRACT
This chapter presents a programme of investigation aimed at the identification of a clinical grammatical marker for the condition of Specific Language Impairment (SLI) in children, beginning with a description of the theoretical framework and predictions. It also presents an overview of available evidence from longitudinal studies of affected and control children and from family history data that indicate a pattern of familiality. The chapter argues a primary benefit from the line of inquiry that helps further our understanding of 'immature' language that may or may not be 'outgrown' and possible causes of grammatical limitations. Accurate and precise specification of the clinical symptoms of language impairment is essential for investigations of genetic factors, as well as for increasing our understanding of the nature of the language impairment and its relationship to other domains of competence, such as nonverbal intelligence.
