This is a systematic presentation of the parametric approach to child language. Linguistic theory seeks to specify the range of grammars permitted by the human language faculty and thereby to specify the child's "hypothesis space" during language acquisition. Theories of language variation have central implications for the study of child language, and vice versa. Yet the acquisitional predictions of such theories are seldom tested against attested data. This book aims to redress this neglect. It considers the nature of the information the child must acquire according to the various linguistic...