Domain-final lengthening and foot-level shortening in spoken English

The literature describes two kinds of durational influence on the syllables of an utterance. They are a lengthening of syllables before many syntactic boundaries ('domain-final lengthening') and a shortening of stressed syllables followed by unstressed syllables ('foot-level shortening'). In the present study we examined the relationship between these two timing phenomena. In particular, we examined the possibility that syntactic boundaries at which lengthening occurs delimit the domains over which foot-level shortening is realized. To test this hypothesis, we varied the syllabic structure of metrical feet spanning word boundaries that either coincided with a noun-phrase (NP)/verb-phrase (VP) boundary or did not. Comparison of stressed syllable durations in these conditions failed to confirm the hypothesis. Instead, unstressed syllables shortened stressed syllables by the same duration across an NP/VP boundary as within a phrase. Our findings suggest that the two effects are independent. The finding that foot-level shortening spans finally-lengthened syntactic boundaries is discussed in relation to theories of the shortening effect.