First International Conference on Spoken Language Processing (ICSLP 90)
This paper describes a speech production model considering the factors such as velum impedance, vocal tract volume inflation, and subglottal system. Based on our measurements of acoustic waveforms and mechanical vibrations at several points of vocal organ, we propose a speech production model having oral-nasal coupling through velum even when it closes. The velum is assumed to be composed of two vibrating plates connected each other by a spring and a mechanical resistance. A syllable /bi/ is synthesized and examined, as an example, by the model considering the velum leakage as well as small inflation of vocal tract volume by inner air pressure at just before mouth opening. As to the speech production model which has both of subglottal structure and supraglottal one, it is shown that the wave-form of glottal flow is changed, and synthesized vowels have zeros in their spectra because of an interaction between sub- and supra-glottal structures through small opening area due to incomplete vocal cords closure.
Bibliographic reference. Suzuki, Hisayoshi / Nakai, Takayoshi / Dang, Jiauwu / Lu, Chengxiang (1990): "Speech production model involving subglottal structure and oral-nasal coupling through closed velum", In ICSLP-1990, 437-440.