A parametric study of the spectral characteristics of European Portuguese fricatives

Studies of Portuguese phonetics and phonology indicate that fricatives are central to some interesting features of the language, yet studies of Portuguese fricatives have been few and limited. In this study, Portuguese fricatives were analyzed in ways designed to enhance our description of the language and to increase our understanding of the production of fricatives. Corpora of Portuguese words containing /f, v, s, z, P, W/, nonsense words of the pattern =V1FV2= that follow Portuguese phonological rules, and sustained fricatives were recorded by four native speakers of European Portuguese (two men, two women). Results of analysis show that more than half of the voiced fricatives devoice; devoicing occurs more often in word-final fricatives. Averaged power spectra were computed for all fricatives and parameterized in order to aid comparisons across speaker and across corpus, and to gain insight into the production mechanisms underlying the language-specific variations. Substantial differences were found between spectra of voiced and unvoiced, same-place fricatives. The parameters spectral slope, frequency of maximum amplitude, and dynamic amplitude, derived from previous studies, behaved as predicted for changes in effort level, voicing, and location within the fricative. Changes in syllable stress, however, did not affect the fricatives in a manner consistent with effort level variation. Some combinations were also useful for separating the fricatives by place or by sibilance. r 2002 Elsevier Science Ltd. All rights reserved.