Abductive and Deductive Change

This article takes as its point of departure an unusual phonological change in a Czech dialect. It then proposes a model of phonological change which would make possible the understanding of structural innovations in the phonology of a homogeneous speech community. The model, which distinguishes two logically different modes of change (abductive and deductive), helps clarify the essential difference between ‘internally motivated’ change and change ‘induced from without’. The model uses our experience of observed phonetic changes, and may consequently have some bearing on our understanding of the structure of phonology.