Measurement of formant transitions in naturally produced stop consonant-vowel syllables.

Formant transitions have been considered important context-dependent acoustic cues to place of articulation in stop-vowel syllables. However, the bulk of earlier research supporting their perceptual importance has been conducted primarily with synthetic speech stimuli. The present study examined the acoustic correlates of place of articulation in the voiced formant transitions from natural speech. Linear prediction analysis was used to provide detailed temporal and spectral measurements of the formant transitions for /b,d,g/ paired with eight vowels produced by one talker. Measurements of the transition onset and steady state frequencies, durations, and derived formant loci for F1, F2, and F3 are reported. Analysis of these measures showed little evidence of context invariant acoustic correlates of place. When vowel context was known, most transition parameters were not reliable acoustic correlates of place except for the F2 transition and a two-dimensional representation of F2 X F3 onset frequencies. The results indicated that the information contained in the formant transitions in these natural stop-vowel syllables was not sufficient to distinguish place across all the vowel contexts studied.