In Qualified Defense of VOT

The VOT measure has been said to provide the single most nearly adequate physical basis for separating homorganic stop categories across a variety of languages, granted that other features may also be involved. That transition duration affects perceived voicing of synthesized initial stops of one specific language, English, has suggested the hypothesis by Stevens and Klatt (1974) that a detector responsive to rapid formant-frequency shifts after voice onset better explains the child's acquisition of the contrast than does some mechanism which responds to VOT directly. If such a detector is part of our biological equipment, then it seems remarkably underutilized in language, for the hypothesis asserts that basic to voicing perception is whether laryngcal signal is or is not present during the interval in which the stop-vowel transition occurs. In effect, the “archetypical” voiceless stop is aspirated. Not only do many languages not possess voiceless aspirates, but even in English aspiration is severely restricted. Of course the VOT measure has its limitations - it is inapplicable to prepausal stops. However, there are much more serious difficulties with the posited detector, since even for the English initial stops there is evidence that the presence of a voiced first-formant transition is not required for the perception of /bdg/, nor does the absence of such a transition necessarily yield /ptk/, provided appropriate VOT values are provided.