Toward a taxonomy of nonmodal phonation

The study of nonmodal phonation, like the study of other aspects of voice quality, spans many disciplines. Descriptions of such phonation abound, but variations in scope, purpose, terminology, measurement technique, and level of description make it difficult to compare vocal phenomena across disciplines, or even across studies within a single discipline. We demonstrate how hypotheses about which kinds of nonmodal phonation types are the same and which are different can be tested by studies of listeners' perceptions. Evidence suggests that period-doubled phonation, amplitude modulations, and vocal fry form perceptually distinctive qualities, which also have consistent acoustic and physiological correlates. Evidence is much more ambiguous for qualities like breathiness and creak, which vary continuously from modal phonation. A common theoretical framework for the description of vocal quality may eventually eliminate many impediments to unified description. (C) 2001 Academic Press.