Time-varying features as correlates of place of articulation in stop consonants.

Running spectral displays derived from linear prediction analysis were used to examine the initial 40 ms of stop-vowel CV syllables for possible acoustic correlates to place of articulation. Known spectral and temporal properties associated with the stop consonant release gesture were used to define a set of three-time-varying features observable in the visual displays. Judges identified place of articulation using these proposed features from running spectra of the syllables /b,d,g/paired with eight vowels produced by three talkers. Average correct identification of place was 88%; identification was better for the male talkers (92%) than the one female talker (78%). Post hoc analyses suggested, however, that simple rules could be incorporated in the feature definitions to account for differences in vocal tract size. The nature of the information contained in linear prediction running spectra was analyzed further to take account of known properties of the peripheral auditory system. The three proposed time-varying features were shown to be displayed robustly in auditory filtered running spectra. The advantages of describing acoustic correlates for place from the dynamically varying temporal and spectral information in running spectra is discussed with regard to the static template matching approach advocated recently by Blumstein and Stevens [J. Acoust. Soc. Am. 66, 1001-1017 (1979)].