Construindo categorias sonoras: o vozeamento de consoantes obstruintes em surdos profundos usuários de língua de sinais (LIBRAS)

This dissertation aims to analyse the voice properties of obstruent consonants in BrazilianPortuguese, specifically the stops [p, b, t, d, k, g], the fricatives [f, v, s, z, ., .] and theaffricates [t., d.], in pre-lingual deaf users of Brazilian Sign Language (Libras). The aim ofthe project was to investigate the contribution of dactylology (Libras manual alphabet) in theconstruction of sound categories by the deaf. Six deaf subjects and a control group of sixsubjects with hearing participated in five experiments. The experiments were composed oftasks designed to nominate words and logatomes in communicative speech and lip reading,dactylology and printed illustrations. The obstruent consonants investigated were located atthe initial position of the word. The deaf participants were between the ages nine to 14 andthose with hearing, between 18 and 30. All responses were recorded and filmed and the Praatsoftware program provided the acoustic analysis. The following acoustic measures wereinvestigated: the VOT (Voice Onset Time) of stops, duration of fricatives, VOT and durationof affricates, the presence/absence of bar voicing and the duration of the vowel following theobstruent. The results showed that the phonetic inventory of the deaf is reduced whencompared to those with hearing, being that all the deaf participants manifested only voicelessobstruents. The VOT values for stops were always positive, showing the presence of solelyunvoiced sounds. The absence of the bar voicing in the spectrogram confirmed that allobstruents investigated were unvoiced. VOT measures for stops, duration of fricative, VOTand duration of affricates presented an unsystematic characterization regarding the propertiesof voicing for obstruent consonants amongst deaf participants. It was not possible to find finephonetic detail generalizations which expressed the voice contrast in obstruents since all deafparticipants presented only voiceless sounds. Complementary research showed that thelengt...