Synthesis of Speech From a Dynamic Model of the Vocal Cords and Vocal Tract

Abstract

We describe a computer model of the human vocal cords and vocal tract that is amenable to dynamic control by parameters directly identified in the human physiology. The control format consequently provides an efficient, parsimonious description of speech information. The control parameters represent subglottal lung pressure, vocal-cord tension and rest opening, vocal-tract shape, and nasal coupling. Using these inputs, we synthesize vowel-consonant-vowel syllables to demonstrate the dynamic behavior of the cord/tract model. We show that inherent properties of the model duplicate phenomena observed in human speech; in particular, cord/tract acoustic interaction, cord vibration, and tract-wall radiation during occlusion, and voicing onset-offset behavior. Finally, we describe an approach to deriving the physiological controls automatically from printed text, and we present sentence-length synthesis obtained from a preliminary system.