Identification and Discrimination of Phonemic Vowel Duration

Abstract

Hunter College, New York, New York Experimental findings on the perception of certain consonants are consistent with an articulatory feedback hypothesis that relates discontinuity of articulation to the discontinuous perception of what would be an acoustic continuum. An extension to a phonemic distinction in which an articulatory and an acoustic continuum are possible would lead one to expect no discrimination peaks in the perception. This extension of the hypothesis has been tested on the feature of relative vowel duration, by which words can be minimally distinguished in the Thai language. Fourteen length variants generated by tape cutting from the long member of a minimal pair of words were identified phonemically by Thai subjects with a definite but not sharp phoneme boundary. In forced-choice discrimination tests, the Thai speakers showed no discrimination peak at the phoneme boundary, and, in mimicry experiments, they tracked the stimuli continuously, equally well at the phoneme boundary and within the phoneme category. These results contribute to the validation of the hypothesis. For the purpose of making a cross-language comparison, American subjects were also tested. In their mimicry and discrimination of the stimuli, they behaved as the Thai did. In the identification test, the American subjects labeled the stimuli as “short” or “long” (since no phoneme boundary was relevant), but showed a wider range of indeterminacy and greater context effects than the Thai.