Experimental phonetic study of the timing of voicing in English obstruents

Abstract

The treatment given to the timing of voicing in three areas of phonetic research -- phonetic taxonomy, speech production modelling, and speech synthesis -- Is considered in the light of an acoustic study of the timing of voicing in British English obstruents. In each case, it is found to be deficient. The underlying cause is the difficulty in applying a rigid segmental approach to an aspect of speech production characterised by important inter-articulator asynchronies, coupled to the limited quantitative data available concerning the systematic properties of the timing of voicing in languages. It is argued that the categories and labels used to describe the timing of voicing In obstruents are Inadequate for fulfilling the descriptive goals of phonetic theory. One possible alternative descriptive strategy is proposed, based on incorporating aspects of the parametric organisation of speech into the descriptive framework. Within the domain of speech production modelling, no satisfactory account has been given of fine-grained variability of the timing of voicing not capable of explanation in terms of general properties of motor programming and utterance execution. The experimental results support claims In the literature that the phonetic control of an utterance may be somewhat less abstract than has been suggestdd in some previous reports. A schematic outline is given, of one way in which the timing of voicing could be controlled in speech production. The success of a speech synthesis-by-rule system depends to a great extent on a comprehensive encoding of the systematic phonetic characteristics of the target language. Only limited success has been achieved in the past thirty years. A set of rules is proposed for generating more naturalistic patterns of voicing in obstruents, reflecting those observed in the experimental component of this study. Consideration Is given to strategies for evaluating the effect of fine-grained phonetic rules In speech synthesis