Perception of consonant length: voiceless stops in Turkish and Bengali

Abstract

The goal of the present research was to investigate the extent to which acoustic cues other than the silent gap corresponding to closure duration might figure in the discrimination of geminate and non-geminate voiceless stops. The method, adapted from earlier studies on duration cues, was to create two sets of stimuli with the length of the silent interval varying incrementally between that of a non-geminate and that of a geminate. One set was made by artificially lengthening the silent interval of an original non-geminate in 10 ms steps up to the length of a geminate, and the other set was made by shortening an original geminate in the same manner. Starting with recorded minimal word pairs with geminate and non-geminate stops in Turkish and Bengali, sets of stimuli were constructed as described above. These stimuli were presented to native speakers of the respective languages in a word identification task, and the results were charted to see whether the identification curves were the same for the original geminates as for the original non-geminates. The result was that the curves did differ, the original geminates being identified as geminates slightly more frequently than original non-geminates at closure durations between 120 and 160 ms. The difference was statistically significant for at least some points on the curve. However, in contrast to earlier studies on consonant duration contrasts, the displacements found were less than 10 ms on the time axis, and the region of significant difference between the identification curves confined entirely to a segment of the time continuum in which no naturally occurring stimuli are found. Our conclusion is that in actual speech recognition there is no evidence that cues other than closure duration play a role in the discrimination of geminate and non-geminate stops in these languages.