Perceptual judgment of abruptness of voice onset in vowels as a function of the amplitude envelope.

Four experienced speakers were trained to produce isolated vowels with different degrees of abruptness of voice onset while keeping the maximum sound level and the duration of the sounds constant. A total of 420 vowel tokens were rated for abruptness of voice onset by 11 trained speech scientists in order to study the reliability of the ratings, which was found to be moderately high (r1,1 = .74 with an extremely large range of the stimuli). Next a number of simple descriptions of the rising slope of the amplitude envelope are developed. It appears that the logarithm of the time needed for the amplitude envelope to rise from 10% to 90% of its eventual maximum level is the best predictor of perceived abruptness of voice onset of the measures examined in this study. Based on this result, an inexpensive instrument is described that can help the speech-language pathologist in assessing abruptness of voice onset in clinical practice.