Language Acquisition and Change

This is a theory of diachronic change based on studies of language acquisition. This monograph addresses diachronic change of languages in terms of a restructuring of speakers' internal grammatical knowledge. The authors answer questions about the circumstances surrounding grammatical change and attempt to identify causes, constructing a general theory of diachronic change consistent with insights from language acquisition. Historical linguistics commonly invokes the child as the principal agent of change. The authors therefore address the topic against the background of insights gained from extensive research into monolingual and bilingual language acquisition. In view of evidence showing that children are remarkably successful in reconstructing the grammars of their ambient languages, the authors reconsider a number of commonly held explanatory models of language change, including language contact and structural ambiguity in the input. Based on a variety of case studies, the discussion of these topics sheds new light on phenomena of change which have occupied historical linguists since the nineteenth century. In an innovative take on the subject, the authors argue that morphosyntactic change in core areas of grammar, more specifically in grammatical domains referring to parameters of Universal Grammar, typically happens in settings involving second language acquisition. The children acting as causal agents of restructuring are either (child) second language learners themselves or are continuously exposed to the speech of second language speakers of their target languages.