Perceptual cues to the voiced-voiceless distinction of final fricatives for listeners with impaired or with normal hearing.

Cues to the voicing distinction for final /f,s,v,z/ were assessed for 24 impaired- and 11 normal-hearing listeners. In base-line tests the listeners identified the consonants in recorded /d circumflex C/ syllables. To assess the importance of various cues, tests were conducted of the syllables altered by deletion and/or temporal adjustment of segments containing acoustic patterns related to the voicing distinction for the fricatives. The results showed that decreasing the duration of /circumflex/ preceding /v/ or /z/, and lengthening the /circumflex/ preceding /f/ or /s/, considerably reduced the correctness of voicing perception for the hearing-impaired group, while showing no effect for the normal-hearing group. For the normals, voicing perception deteriorated for /f/ and /s/ when the frications were deleted from the syllables, and for /v/ and /z/ when the vowel offsets were removed from the syllables with duration-adjusted vowels and deleted frications. We conclude that some hearing-impaired listeners rely to a greater extent on vowel duration as a voicing cue than do normal-hearing listeners.