SPECTRAL AND TEMPORAL PROCESSING IN BALINESE VOWEL OF NON-FLUENT APHASIA

Abstract

Acoustic investigation on Balinese vowel of non-fluent aphasia (NFA) has not been previously paid attention yet. Thus, this study examined the acoustic abnormalities of vowel articulation for patients with NFA. Therefore, spectral and temporal charateristic of their vowel sound are essentially searched by comparing the formant value and prosodic features with the normal vowel articulation. Speech output of two patients were observed and analyzed by using  Praat and the data were described by implementing the theory of clinical phonetics and acoustics. The spectral analysis showed that the inaccurate constriction of the tongue in vowel articulation affected the range of oral tract (F2), pharynx space (F1), and shape of the lips (F3).  Furthermore, the lesion in Broca’s area affected the temporal features of the sounds, such as the lower pitch, lower intensity and longer timing especially voicing environment. The vowels preceded by voiced consonants were significantly longer than those preceded by voiceless ones. So, the highly complex vowels tend to be articulated inaccurately due to articulatory implementation deficit. This finding is consistent with previous results that the spectral and temporal distortion are primarily phonetics rather than phonological planning program.