Crosslinguistic acoustic categorization of sibilants independent of phonological status

Abstract The main object of this paper is to provide an acoustic characterization of a stable phonetic contrast across a number of variable dimensions such as vowel context, gender, language, and, in particular, phonological status. The contrast that is investigated is between the dental/alveolar sibilant fricative [s] and its palatoalveolar counterpart [∫]. The phonological feature involved in this distinction is [anterior]. Data from three languages are analysed, where the feature has a different phonological status. In English, both fricatives are independent phonemes, and the feature [anterior] is thus contrastive. In Bengali, [s] is an allophone of the phoneme /∫/, whereas in Dutch, [∫] is an allophone of the phoneme /s/. Power spectra, obtained by placing a 40 ms window in the middle of the friction, display a consistent pattern of differences between [s] and [∫] across the three languages independent of gender and vowel contexts. This difference is then quantified by a metric, based on the slopes of the spectral envelope below and above 2.5 kHz. It turns out that all three languages distinguish between [s] and [∫] in much the same way, but that the boundary values of the metric show some variation. However, this variation cannot be related to any of the variable factors mentioned above, but seems to be speaker-dependent. It is concluded that phonological status does not affect the realisation of this phonetic distinction, and that the appropriate acoustic correlate displays a relative rather than an absolute kind of invariance.