David M. Hogue
Robert J. Porter
Dept. of Psychol., Univ. of New Orleans, Lakefront, New Orleans, LA 70148
The value of examining various aspects of speech production from a nonlinear, dynamic systems point of view has been suggested by recent reports [e.g., J. A. S. Kelso and B. Tuller, J. Physiol. 246, R928--R935 (1984)]. Utilizing principles from physical biology the relationships between speech breathing, length of utterance, and upper airway resistance were examined. A simplified biological state equation served as the model [P. N. Kugler and M. T. Turvey, Information, Natural Law, and the Self-assembly of Rhythmic Movement (Erlbaum, Hillsdale, NJ, 1987)]. Speaking tasks were varied on reiterant versus meaningful speech, length of utterance, normal fundamental frequency speech, whispered speech, and monotonic speech. Upper airway resistance values were calculated as ratios according to differential airflow as measured by a Rothenberg mask. Duration and depth of inspiration and expiration were measured with a Respitrace, and acoustic information was obtained from digitized speech samples using the program CSPEECH. Subjects demonstrated strong relationships between utterance length and volume of expired air and between utterance length and upper airway resistance. Experimentally derived exponents for the volume and resistance components of the biological state equation closely estimate those predicted. This presentation is a followup to the study presented in Houston, Fall 1991; the current study has made more accurate measures of upper airway resistance and has additional conditions. [Work supported by the Dept. of Psychol. and Chancellor's Fellowship.]