A nasalidade vocálica do português brasileiro : evidências empíricas para a sua representação

Abstract

This study investigates the phonological status of nasal vowels in Brazilian Portuguese using acoustic and perceptual data. The main objective of this work is to investigate, through the analysis of experimental data and based on Gestural Phonology (BROWMAN; GOLDSTEIN, 1986), arguments for the phonological representation of nasal vowels in Brazilian Portuguese, whether they are constituted by one or two segments. The specific objectives of the study are: to assess the contribution of employing different analysis experiments (acoustic and perceptual) to the discussion of the phonological representation of nasal vowels; to describe the characteristics of the nasal acoustic signal of nasal vowels in Brazilian Portuguese; to investigate the influence of the acoustic features of nasal vowels on the perception of these segments as phonological units; to acoustically and perceptually compare the behavior of nasal vowels in their different structures with vowels nasalized by a following consonant; and to formalize the nasality in Brazilian Portuguese, based on gestural principles, and thus, to explain the composition of the phonological representation of nasal vowels using Gestural Phonology. To achieve these objectives, two experiments were conducted, one acoustic and the other perceptual. The acoustic experiment was conducted at the Laboratoire de Phonétique et Phonologie, at Université Paris III – Sorbonne Nouvelle, in Paris/France. The corpus of this experiment comprises pairs of trisyllabic pseudowords and paroxytones, designed with the aim of presenting the distinctive vowel nasality. These pseudowords were inserted into carrier phrases, along with the five nasal vowels of Brazilian Portuguese – [ɐ̃ ɐ̃], [ẽ ], [ĩ], [õ], [ũ ] – together with pseudowords containing their oral counterparts. These vowels are distributed between pretonic and tonic syllables, and their preceding contexts consisted of the stops [p t k], while their following contexts were formed by voiceless stops [p, t, k] and voiceless fricatives [f, s, ʃ']. The experiment involved 5 speakers, who produced 598 data. The oral and nasal acoustic signals were observed and analyzed – using the software PRAAT – with the aim of better understanding the propagation of nasality in these segments. The results indicated: (i) the predominance of vowels composed of the acoustic moments Oral+Nasal+Murmur (O+N+M) and Nasal+Murmur (N+M) to the detriment of Oral+Murmur (O+M); (ii) the absence of a coarticulatory nasality anticipation pattern, which was observed for nasalized vowels, with no considerable differences in the relative duration of the oral acoustic moment, regardless of the following articulation point, and (iii) similarities between the timing of the onset of soft palate lowering observed by Amelot et al. (2008) for French monophonemic vowels and our results. The second experiment, related to perception, had its data collection conducted at FONAPLI – Laboratory of Applied Phonetics –, at the Federal University of Santa Catarina, in Florianópolis. Thirteen female listeners participated in identification and discrimination tests – created using the Psychopy software – generating a total of 6396 data. Stimuli were created and manipulated in order to: evaluate the perception of nasal vowels, considering their different compositions (ONM, NM, and OM); investigate the role of murmur in the perception of nasal vowels in Brazilian Portuguese, considering their different compositions; and assess the perceptual differences that arise between nasal vowels and nasalized vowels. The main results indicated that: (i) the phase composition does not appear to be influenced by dialectal variation, as the results from the pilot test and the final collection, which included informants from different backgrounds, were quite similar; (ii) the OM composition does not seem to be satisfactorily recognized by the informants, showing longer reaction times and a significant number of errors in stimuli related to reliability; (iii) ONM and NM nasal vowels, even without murmur, are perceived as nasal, whereas OM is perceived as oral; (iv) nasalized vowels without a consonant are perceived as oral, indicating distinct perceptions for these segments. The analysis through Gestural Phonology – especially the formalization through gestural scores – allowed for the revelation of a pattern in the phase of the articulatory gestures involved, particularly for the vowels with ONM and NM compositions, contrary to what would be expected for a phonological representation consisting of two segments, forming a VC syllable. However, the OM composition can be formalized through two representations: one that exhibits an antiphase pattern between the velic gesture and the vocalic gestures, and another in which the gestural overlap between the velic gesture and the gestures of the following consonant accounts for the absence of nasal phase, thus not being associated with an antiphase relationship. Therefore, as the results from the analysis of experimental data through gestural scores indicate, a phonological representation of Brazilian Portuguese nasal vowels can be inferred as being composed of only one segment.