Rate and Duration of Change in Formant Frequency as Cues for the Identification of Speech Sounds
Louis J. Gerstman, Alvin M. Liberman, Pierre C. Delattre, F. S. Cooper · The Journal of the Acoustical Society of America · 1954
Earlier experiments have shown that the direction and extent of the frequency changes in the formants of synthetic speech sounds can serve as effective cues for the identification of certain phones according to place of production. Examination of spectrograms and exploratory work with synthetic speech has suggested that the temporal course of these changes may provide a basis for distinguishing among some classes of speech sounds that differ in manner of production. It was found in the present experiment that the tempo of the change between two fixed formant frequencies is, in fact, sufficient to enable naive listeners to distinguish rather reliably among stop-consonant-plus-vowel (e.g., ba), semi-vowel-plus-vowel (e.g., wa), and a sound of shifting vowel color (e.g., ua). Further experiments suggest that the duration of the frequency changes are more important than the rate at which the changes occur.