Differentiation of /p/ and /b/ from Spectrographic-Intraoral Air Pressure Comparison

Abstract

Recordings of intraoral air pressures nd acoustic signals were obtained from four speakers repeating the syllables [pɑ] [bɑ] [ɑp] and [ɑb]. Intraoral air pressure and formant patterns were simultaneously obtained and displayed on a spectrogram, which permitted measurement of the time relationships of the two events. Comparisons were made of components of the pressure wave trace to either the onset or termination of the formant traces of the vowels. The ratio of the drop in time of pressure from peak to vowel formants onset or termination, which relates to the opening of the lips, significantly differentiated between all four syllables. The pressure rise-time ratio, which corresponds to lip closure, distinguished between /p/ and /b/ in both syllabic positions. These data indicate that the activity during the “silent gap” or stop segment of these utterances contributes significantly to the differences between them.