The role of rate of transition in the perception of place of articulation

Abstract

Listeners can reliably identify the place of articulation of bilabial and alveolar stops in severely truncated CV syllables from just the initial 20 ms, but they need 40 ms or more to identify a velar. The need for a longer interval may reflect listeners' expectations that rate of transition should be slower for velars because of the slower opening gesture at this place of articulation [Kewley‐Port et al., J. Acoust. Soc. Am. 73, 1779–1783 (1983)]. This paper investigates the perceptual effects of differences in rate of transition in two experiments. First, synthetic CV syllables, where the direction and magnitude of the F1, F2, and F3 transitions matched natural [ba,da,ga] syllables, but where the transition durations were varied in 15‐ms steps between 15 and 120 ms were presented to listeners for two‐interval, forced‐choice discrimination and for identification along a stop—glide dimension. If listeners expect longer transitions with velars, then they should accept stimuli with longer transitions as stops when the formants indicate a velar than when they indicate a bilabial or alveolar. Second, variation in F2 and F3 transitions between values appropriate for [da] and values appropriate to [ga] were combined with variation in the rate of transition; rate of transition was varied in 5‐ms steps between 20 and 60 ms. These stimuli were also presented to listeners in two‐interval, forced‐choice discrimination and identification of place of articulation tasks. It is expected that faster rates of transition will shift listeners' response to stimuli with F2 and F3 transitions near the [d]/[g] boundary toward [d] and slower transitions will shift them toward [g].