TEMPORAL AND SPECTRAL CUE USE FOR INITIAL PLOSIVE VOICING PERCEPTION BY HEARING-IMPAIRED CHILDREN AND NORMAL-HEARING CHILDREN AND ADULTS

The influence of voice-onset time (VOT) and vowel-onset characteristic s on the perception of the voicing contrast for initial plosive conson ants was examined for hearing-impaired children, and normal-hearing ch ildren and adults. Listeners identified spoken 'DAD'-'TAD' stimuli con trolled for VOT and vowel onset characteristics. Only six of 16 hearin g-impaired children appropriately identified the exemplar DAD and TAD stimuli used as endpoints of VOT continua. For this group of six heari ng-impaired children, a longer VOT than for the normal-hearing listene rs was required to elicit /t/ rather than /d/ percepts. The VOT region of perceptual cross-over in labelling widened progressively from norm al-hearing adults to normal-hearing children to hearing-impaired child ren. Generally, longer VOTs were required to yield /t/ perception in t he context of the DAD vowel than with the TAD vowel. These 'vowel stem ' effects on VOT boundary were inconsistent for the hearing-impaired c hildren, and weaker for the normal-hearing children than for the adult s. These spoken stimuli produced results for VOT cue use that generall y parallel those obtained in studies with synthetic stimuli.