Relative Perceptual Cue Strength for Voiced Stop Consonants

Abstract

The relative strength of noise bursts and vocalic transitions as perception cues of word initial voiced stop consonants in CVC nonsense utterances was investigated using a tape splicing technique. All possible combinations of noise bursts and vocalic transitions in CVC utterances (using /b, d, g/ as initial consonants, /i, æ, a, u/ as vowel, and /z/ as the final consonant) were obtained by tape splicing-substitution techniques. Temporal segmentation was accomplished by inserting a piece of splicing tape before each utterance. A sonogram was made on which the location of the tape splice in relation to the utterance was shown. Measurement of the sonogram and conversion to distance along the tape allowed for a precise tape splice for substitutions of noise bursts and vocalic transitions (cue switching). The first 10 msec of noise burst and the following 50 msec vocalic transition were systematically substituted for presentation to a group of listeners. For example, each listener heard /biz/ produced in a normal manner, a silence inserted for the /b/ burst plus /iz/, and /b/ burst attached to all combinations of /iz/ which originally had been produced with either /d/ or /g/ as the initial consonant. Similiarly vocalic transitions were varied, so that each transition was substituted into all other CVC utterances. The results of this investigation indicate a slight preference for listeners to identify CVC syllables on the basis of the noise burst rather than on the basis of the transitional information.