Perception grammars and sound change
The acoustic consequences of gestural overlap afford listeners multiple, time-varying cues for a given linguistic percept. Findings from “offline” perceptual tasks and “online” real-time processing converge in demonstrating that listeners attend to the dynamic cues, tracking the coarticulatory information over time. These findings also converge in showing that listeners systematically differ in their perceptual weighting of the information contributed by the coarticulatory source and its effects; that is, listener attention is selective. One factor contributing to these listener differences in perception grammars may be listener-specific experiences with particular coarticulatory patterns. However, another factor is the quasi-systematic nature of coarticulatory variation, which provides listeners with covarying cues and therefore multiple <i>possible</i> weightings that are fully consistent with the input. Of particular interest for sound change are “innovative” listeners, for whom the coarticulatory cues are heavily weighted. These listeners’ perception grammars have the potential to contribute to changes in which the coarticulatory effect is requisite and its source may be lost – but only insofar as those grammars are publicly manifested. Such manifestation is likely to occur in conversational interactions either through innovative listeners’ expectations about coarticulated speech or through those listeners’ own productions.