Abstract
<jats:p>Theories of diachronic change frequently assume that diachronic reanalysis is closely related to language acquisition. A critical discussion of research on first language acquisition as the locus of diachronic change shows, however, that this relation is not as straightforward as often assumed. Based on the assumption that diachronic reanalysis consists in a restructuring of core grammatical properties, we argue that the plausibility of alleged causes of reanalysis needs to be aligned with insights gained by research on different types of acquisition. In particular, as demonstrated by research on child first language acquisition, reduced frequency of occurrence or ambiguity of a construction are unlikely to lead to change in the course of language transmission across generations, as children are able to cope with variation and inconsistency in the primary linguistic data (PLD) and to acquire infrequent and residual structures. Language contact is also neither a sufficient nor by itself a likely cause of reanalysis. Bilingual populations may show peculiarities in their speech, and they may accelerate ongoing grammatical changes, but bilingual first language acquisition does not normally lead to a restructuring of grammar. L2 acquisition is a more likely locus of reanalysis, either when L2 learners interact with children acquiring an L1 and provide the trigger of change, or when they represent a quantitatively and qualitatively strong social group exerting influence on the entire speech community.</jats:p>