Aim of the present study was to give an optimal definition of the boundary between vowel categories in terms of perceptual and acoustic parameters. To reach this target we performed a comparison between the results of vowel identification tests performed with synthetic speech sounds and tests with vowel stimuli segmented from natural connected speech. Two experiments aiming at the definition of vowel boundaries will be illustrated. In both experiments our attention is directed to that portion of the F1/F2 diagram which defines the area of existence of Italian vowels [a, E, e, i]. The results of this work lead us to wonder on the opportunity of looking for fixed boundaries, weather they are acoustical or perceptual. Our conclusions rather seems to confirm the presence of a great adptivity in the perceptual listener's capacity.
Bibliographic reference. Cutugno, Francesco / Savy, Renata (1995): "On phonetic boundaries across categories for synthetic and natural vocalic speech sounds", In EUROSPEECH-1995, 2297-2300.