The chapter presentations examine language development across a variety of populations of children, from those with Specific Language Impairment to second language learners. The chapter contributors discuss criteria for the definition of SLI, compare and contrast SLI with profiles of children with other disorders and dialects, and offer a comprehensive look at the Whole Human Language, which ties together spoken and sign languages.

Methodological concerns that affect the credibility and generalizability of the findings are discussed and controversies between opposing linguistic approaches to language acquisition are presented.

The conceptual thread that gradually reveals itself as the chapters unfold is a theoretical issue of central importance to cognitive theory, as well as to our understanding of the biological correlates of language—the variability that linguistic competence can take in children as they develop.

Language Competence Across Populations: Toward a Definition of Specific Language Impairment is an essential volume for advanced students and scholars in linguistics and psychology who have an interest in language acquisition and language disorders, as well as for the clinical professionals dealing with children with language impairments