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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.

In current phonological theory, geminate consonants are distinguished from non-geminates by a difference in units on the timing tier in an autosegmental representation, other features being the same; and while there are geminates of three kinds according to how they arise (tautomorphemic, concatenated, and derived by total assimilation), the representation of all three on the timing tier is the same. The present paper investigates two questions: what exactly is the acoustic difference between geminate and non-geminate consonants (focusing on voiceless stops); and are there acoustic differences between geminates derived from different sources phonologically. We examined two unrelated languages, Bengali and Turkish, and found that the single overriding cue distinguishing geminate from non-geminate stops is the duration of the closure. In Bengali, we examined geminate stops derived from the three different sources and found no significant difference in closure duration. Thus the autosegmental representation of the difference between geminate and non-geminate consonants in terms of a timing difference is vindicated, and we have an acoustic correlate for the timing measure. As a secondary result, we have shown that total assimilation leading to the formation of a geminate constitutes an instance of neutralization that is phonetically complete.