David Lightfoot,The development of language: acquisition, change, and evolution. (Maryland Lectures in Language and Cognition 1.) Malden, MA & Oxford: Blackwell, 1999. Pp. xii+287.

The central thesis of The development of language is that there are noprinciples of grammatical change, so that ‘historicist’ or deterministicapproaches to diachronic change are misguided. Instead, Lightfoot arguesthat language change can only be understood by taking the perspective of the‘growth’ (i.e. acquisition) of an individual's biological grammar, which mayend up with a different parameter setting from the parent's generation whenthe trigger experience changes. Such events of grammatical change areabrupt and unpredictable, and Lightfoot suggests that they can beunderstood better from the point of view of catastrophe theory and chaostheory than under a deterministic theory of history as was common in thenineteenth century.