An acoustic and perceptual study of initial stops produced by profoundly hearing impaired adolescents

This study investigated the role of Voice Onset Time (VOT) as perceptual cue to the aspiration contrast of Cantonese initial stops produced by adolescent profoundly hearing impaired speakers. Speakers with normal hearing signalled the aspiration contrast through VOT differences. Hearing impaired speakers produced initial stops with no significant VOT differences between aspirated and unaspirated stops; the accuracy of perception were above chance level for unaspirated stops but were below chance level for aspirated stops. Discriminant analysis conducted on data from a perceptual task showed that listeners with normal hearing relied on VOT cue for aspiration contrast of initial stops produced by control speakers. By contrast, stops produced by the hearing impaired speakers were not distinguished by listeners on the basis of VOT in that listeners were able to rely on VOT as a perceptual cue only to unaspirated stops, but not to aspirated stops.