Acoustic analysis of oral vowels produced by people with t21: a contrast between conquistenses and porto-segurenses speakers

Abstract

This dissertation presents an acoustic phonetic study of the oral vowels produced by four (04) people with T21, born in two cities in Bahia, Porto Seguro and Vitória da Conquista. It is based on the Theory of Speech Production or Theory Theory Filter by Fant (1960), which has subsidies to explain the relationship between changes in the vocal tract and the acoustic quality of the sound. From an articulatory point of view, vowels are characterized by the height of the tongue, its advance and retreat on the horizontal axis and still labialization, however, given the absence of clear boundaries between one segment and another, the acoustic study, through the measurements of formantic frequencies (F1, F2, F3) provide greater precision in identifying the segment produced and its quality. In this research, we analyzed a corpus of words contemplating the vowel segments in the pretonic, tonic and final untoned syllable positions, the data were recorded in an acoustically treated environment, the images were presented in slides for appointment. Subsequently, the average values ​​of the frequencies of the first three formants, henceforth F1, F2 and F3, were extracted using the Praat program (BOERSMA; WEENINK, 2006), then the analysis of the Coefficient of Variance (CV) was performed, using the statistical program. Bioestat (AYRES et al., 2014), the purpose of this test was to identify how far the data were from the average, high values ​​indicated greater variability and heterogeneity. The Coefficient of Variation of people with Down in the city of Porto Seguro and Vitória da Conquista showed greater variations in F1 and F2, they are related to the height of the tongue and its displacement or retreat. The hypothesis that guided this research was that the oromiofunctional alterations of the Porto-Seguro people with Down will have an impact on the articulatory and acoustic configuration of the vowels they produce, just as it happens in the Conquista dialect as attested by Oliveira (2011). The objectives were to acoustically describe the oral vowels produced by people from Porto Seguro with Down syndrome, to buy with data from people with Down syndrome in Vitória da Conquista, to check if there are dialectal and acoustic differences between the oral vowels produced by people with Down. The findings showed that people with T21, even with myofunctional changes, manage to adjust their articulatory trajectories while maintaining the distinction and opposition between the vowel segments. However, the acoustic characteristics obtained by the analysis of the formants showed that there is a difficulty in the movements of closing / opening the jaw and retraction and advance of the tongue in people with T21, as well as difficulty in maintaining the expiratory force necessary to distinguish the syllabic tone.