Differing Pharynx Shapes and Sizes for Vowels
H. M. Truby · The Journal of the Acoustical Society of America · 1964
It is an acoustic commonplace that sound derives from motion, and it is clear that the sounds of speech derive from the act of speech. Physiologically speaking, then, speech is pattern-conditioned articulatory modification of physically generated vocal-tract-amplified sound. One of the byproducts of pattern-conditioned articulation is inherent involuntary action interrelated with the projected voluntary action, including muscular and other motor preadjustments anticipatory to segmental speech-sound-nucleus phenomena. Both cinéradiographic and sound spectrographic analysis demonstrate these anticipative adjustments, and cinéradiography, by revealing normally inaccessible dimensions defining the physical state of the vocal-tract cavities, clarifies spectral shapes apparent on sound spectrograms but not always deducible from the referent perceived speech signal. An x-ray motion film of the production of 15 isolated General American vowels discloses the drastically varying cavity sizes and contours from vowel to vowel and thus divulges formant-cavity information critical for reliable automated speech-simulation and -detection research.