Abstract:
The allophonic variation of liquids in American English prompted a study examining the findings of Mann [Percept. Psychophys. 28, 407--412 (1980)], Fowler et al. [Percept. Psychophys. 48, 559--570 (1990)], and Liberman [Speech (1996)], who used the F3 transition as the primary cue for synthesizing [da] vs [ga] following [al] and [ar]. The disyllables /al--da/, /al--ga/, /ar--da/, and /ar--ga/ were recorded in a carrier sentence by two male and two female speakers of midwestern English at three different speaking rates, and the spectra and durations of the liquids, stops, and vowels were analyzed. Acoustic analyses indicate structural variation: The F3 transitions of [da] and [ga] by themselves are not stable correlates in these contexts, notwithstanding data used in arguments for the perceptual invariance of articulatory gestures in liquid--stop sequences. Regularities were also found: The liquids systematically affect the F2 and F3 of the vowel in the following stop--vowel sequence, not only the onset value of F3. In addition, each speaker encoded segments in his/her own systematic way over variable rates, which extends Gay's findings [J. Acoust. Soc. Am. 63, 223--230 (1978)] to tokens with coarticulatory effects. These data will help assess alternative acoustic cues in future perceptual experiments.