Psychoacoustic evaluation of acoustic features distortion in fricative consonant of speech

The present study investigated the perceptual discrimination between typical (normal) acoustic features duration and intensity in word-initial fricative consonant /integral/ and atypical duration (shortened or lengthened) and intensity (weak or strong). Perceptual task distortion contrast was performed in each dimension, duration and intensity, as well as in two-dimensional interaction. Stimulus was the word Lcuma/ with fricative /integral/ in the initial position. Duration and intensity of /integral/ were synthesized from typicaly pronounced stimuli in 16-step continuum from 135 ms to 300 ms and from -18 dB to +4.5 dB, respectively. Eight speech-language pathologies (SLPs) performed perceptual task distortion contrast in these two dimensions. Results are presented in the form of identification functions. First experiment tested two-choice decision and three-choice decision tasks in identification of distortion in time domain (shortened/normal/lengthened frictive), second experiment analyzed distortion in intensity domain (weak/normal/strong frictive), third experiment examined mutual interaction of distortion in duration and intensity, and forth experiment analyzed two-dimensional perception of simultaneous distortion in both domains, time and intensity. The results indicate regions of typical and atypical values for duration and intensity of fricative /integral/, in Serbian language, and also indicate that distortion in intensity domain does not influence perception of distortion in time domain, except in the case of weak friction. In two-dimensional perception of normal fricative /integral/, the dimension duration has higher perceptual significance over dimension intensity, whereas in perception of distorted fricative the dimension intensity has higher perceptual significance over dimension duration. In two-dimensional perception SLPs reported that they selectively recognize at first the dominant distortion and then another distortion. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

This study investigated the perceptual discrimination between typical and atypical duration and intensity of the fricative consonant /integral/. Results indicated regions of typical and atypical values for duration and intensity of the fricative in Serbian language, and showed that intensity distortion does not influence perception of distortion in time domain, except in the case of weak friction. In two-dimensional perception, duration had higher perceptual significance for normal fricative, while intensity had higher perceptual significance for distorted fricative. SLPs reported selectively recognizing the dominant distortion first in two-dimensional perception tasks.