PURPOSE: to investigate, using an acoustic analysis, the establishment of phonological contrast between alveolar and velar stop sounds in a child with phonological disorders that neutralizes this contrast. METHODS: productions of stop /t/ and /k/ sounds combined with the vowels /a/ and /u/ in the stressed position were investigated in two male children between 5 and 6-year old, one with phonological disorders and the other with no disorder. The analyzed acoustic parameters included acoustic waveform inspection, acoustic parameters related to spectral burst characteristics, acoustic parameters related to the characteristics of vowels adjacent to occlusive sounds and acoustic parameters related to temporal patterns of the productions. RESULTS: findings from this study indicated presence of covert contrast in the two stop sounds produced by the child with phonological disorders, marked by both inadequate phonetic cues and adequate phonetic cues, but with insufficient values. Productions of the child without phonological contrast evidenced the use of at least one phonetic cue related to the primary acoustic characteristics of stop segments, which allows for auditory perception of the contrast between /t/ and /k/ sounds. The productions of both children - with and without phonological disorders - were vocalic context dependent. CONCLUSION: a determined phonetic contrast can be understood as a constellation of phonetic cues that vary in terms of their interdependency and/or perceptual significance.
Speech Acoustics; Spectrography; Speech Disorders; Child Language; Child Development
