Production and discrimination of voicing contrast of stops in cases of phonological disorder

The voicing contrast of stops represents a complex acoustic and articulatory coordination, frequently impaired in cases of phonological disorders. Consequently, we believe that the efforts should be carried out in order to understand the factors that influence in the stabilization of that contrast. So, the purpose of this research was correlating the production data and the performance in a discrimination test of the feature [+voice] in children with phonological disorder. Then, five boys who presented phonological disorder, difficulties in the production of voiced stops and other difficulties, were evaluated. Through the pairs of words introduced in carrier phrases, we observed the occurrence of production of positive Voice Onset Time during the [+voice] stops and the duration pattern of the vowels adjacent to the voiced and voiceless stops. The authors elaborated a Stop Voicing Discrimination Test to evaluate the performance of the individuals regarding to the discrimination. The test consists of 12 pairs of words, being only different in the contrast [+voice] and it is represented by pictures. Through a descriptive analysis, no direct relation between difficulties of the production of voicing contrast of stops and auditory discrimination of this sounds was verified, both on the observation of prevoicing production, regarding the pattern production observation of the length of the vowel. Nevertheless, we emphasize that the use of a discrimination test, as well as of acoustical analysis in cases of phonological disorder, should not be ignored by the speech therapist, once those instruments can give important information to a good therapeutic progress.

Child; Speech; Speech Disorders; Speech Acoustics; Spectrography of sound; Speech Discrimination