Kiyoshi HONDA
Form and Function: Another View of Speech Production
Abstract:Form of body determines neural function. The present study discusses
this biological concept as a central issue to explore morphological
foundations of speech function. Physiological studies of vocal
frequency (F0) control and vowel production mechanisms are reviewed
to show evidence that human speech is dependent on unique
morphology of our body. The form of the cervical organs (larynx and
cervical spine) facilitates wide-range F0 change by their movements.
The geometry of the tongue and vocal tract derives compatibility of
vowel's auditory and articulatory pattern, which suggests a functional
linkage between vowel production and perception. Furthermore,
interaction between mechanisms for producing F0 and vowel results in
a constant vocal tract shape for a given vowel with varying vocal tract
length. Neural reflection of the interaction implies an account on the
mechanism of vowel normalization. A unified model of vowel
production and perception is proposed.