Toward a voice source characterization of voice quality

Abstract

Voice source characteristics for voice quality variations in an individual nonpathological speaker are presented. This forms part of an ongoing analysis that is being carried out within the framework of Laver's classification [J. Laver, The Phonetic Description of Voice Quality (Cambridge U. P., Cambridge, 1980)] and is based on multiple repetitions by a trained phonetician of an English prose passage and nonsense materials, with modal (neutral), creaky, breathy, whispery, tense, and lax voice qualities. The objective is to provide an acoustic characterization of different “cardinal” qualities in the terms of both time and frequency domain parameters. Time domain measures are based on inverse filtered data to which a model of glottal flow (the LF model) has been matched. Frequency domain measures are based on spectral sections of the speech waveform and of the glottal waveform. As an initial strategy, templates of the different voice qualities are presented, based on the stressed vowel [æ]. However, data are also presented to demonstrate the considerable modulation of source quality even within what would traditionally be considered a single voice quality. For example, in creaky voice, the degree of creakiness is not uniform, but tends to be most extreme in unstressed syllables and at specific locations related to the prosodic profile of the utterance. Thus the differences between qualities may be more or less great depending on the environment compared. [Work supported by ACCOR, Esprit, BRA, No. 3279, and the Swedish Institute.]