Streams, phones and transitions: toward a new phonological and phonetic model of formant timing

Abstract

This paper presents a new model of formant timing based on the Delta multi-tiered framework for phonology, phonetics and speech synthesis. Central to the Delta framework is an integrated utterance representation, in which multiple synchronized "streams" can simultaneously represent higher-level phonological and lower-level phonetic units and the precise timing between them. The model treats formant transitions as independent units between phones, rather than incorporating the transitions into the phones, as in more conventional models, and it uses Delta’s multiple streams to represent directly the hierarchical linguistic structure of an utterance, such as phonemes, syllables and syllable nuclei. The model presented is for General American English, but is part of a larger universal model being developed for multiple dialects and languages. Evidence for the English model is drawn from the durational behavior of sonorants before voiced and voiceless obstruents, diphthongs in fast and slow speech, and the timing of aspiration. The model leads to a more cogent treatment of formant timing and the segmentation of continuous speech patterns than is possible with conventional models. It therefore promises a unified account of many formerly disparate phonetic phenomena, more straightforward synthesis rules, and a better understanding of the relationship between phonology and phonetics.