O contraste de nasalidade em falantes normais com fissura palatina: aspectos da produção

Abstract

The aim of this work was to study the contrast in the nasality of vowels and consonants in Brazilian Portuguese in normal speakers and speakers with hypernasality, and investigate the influence of syllabic tonicity and emphasis on this contrast. For this purpose, three studies were developed: nasometric, aerodynamic and duration, involving the analysis of a corpus of eight normal speaker informants and eight speakers with hypernasality as a result of cleft palate, all adult men, aged between 20 and 40 years. The corpus was formed by pairs of words with contrast of nasality in the consonant, in different syllabic positions and trios of words with contrast of nasality in vowels, the first being with an oral vowel, the second with a nasal vowel and the third with a nasalized vowel followed by a nasal consonant. The nasometric study showed that normal speakers and speakers with hypernasality expressed the contrast of nasality in their speech by means of higher values of nasalance for the nasal sounds, but that the magnitude of this difference is smaller for speakers with hypernasality. The postonic position appears to favor the contrast of nasality, as well as the position of the word at the end of the phrase for normal speakers, and in the medial position of the phrase, when emphasized, for speakers with hypernasality. The aerodynamic study revealed that normal speakers expressed the contrast of nasality in their speech by means of higher values of oral pressure and lower values of nasal pressure, nasal flow and velopharyngeal area for the voiced bilabial oral consonant, when compared with the bilabial nasal consonant. Speakers with hypernasality express this contrast only with higher values of oral pressure. For normal speakers tonicity did not interfere in the aerodynamic values. The initial tonic and post tonic positions favored the contrast of nasality in speakers with hypernasality by means of increase in oral pressure. The study of duration indicated that normal speakers and speakers with hypernasality expressed the contrast of nasality in their speech by means of longer duration values for nasal sounds than for oral sounds. Speakers with hypernasality presented longer values for oral sounds than normal speakers did. The initial and medial tonic positions seemed to favor the contrast of nasality in relation to duration, as well as the medial position of the phrase. From the three studies conducted, it was concluded that speakers with hypernasality present the same tendency as normal speakers for expressing the contrast of nasality in speech, however, they do so in a lower magnitude, which may not be sufficient to be perceived by the listeners.