The influence of consonant environment upon identification of transitionless vowels

Abstract

Recent evidence suggests that consonant environment influences listeners' identification of vowel quality in CVC syllables. The rapid formant transitions are generally held responsible for this effect. In an attempt to find out if the effect may depend on other factors besides the transitions, we had 19 subjects listen to a randomized series of C1VC2 stimuli constructed as follows: C1 was [s] or [f], C2 was [p] or [t], and V was a monophthongal [i], [u], or one of 13 vowels linearly spaced between those two vowels. The vowels were either 75 or 150 ms in duration and were completely steady-state in both F0 and formant frequencies. Ss were required to report whether a given stimulus contained an /i/ or an /u/. Identification of these transitionless vowels was significantly affected by the consonantal environment. The results are compatible with two hypothesized perceptual effects: (1) Listeners “know” that dental environments perturb [u] towards [i] and thus will accept a more front vowel as [u] in that environment than in a labial environment, other things being equal, and (2) listeners “know” that the vowel in a dental environment which should have minimal transitions is /i/. The implications of these findings for theories of speech perception and sound change will be discussed. [Supported by NSF and NIH.]