Articulatory and acoustic characteristics of whistled fricatives in Changana

Phonemic whistled fricatives are reported in only a few languages, including several Bantu languages in what is traditionally known as Zone S. Unlike typical voiceless fricatives, the voiceless whistled fricative is a periodic sound with a relatively simple harmonic structure. In comparison to plain sibilant fricatives, whistled fricatives are marked by a relatively high-amplitude, narrow-bandwidth peak. While some diachronic and phonological analyses make use of the labial feature to explain the development and behavior of the sound, it is not clear that lip-rounding is necessary or primary for the production of the whistled fricative. In fact, it has been claimed that whistled fricatives in Zone S manifest little to no lip-rounding. In this study, the voiceless whistled fricative of a single speaker of Changana (Hlengwe dialect) is described with reference to both acoustics and labial configuration. It is observed that Changana's voiceless whistled fricative manifests a degree of lip-rounding somewhat less than the rounding that occurs in the non-whistled fricative found in [usu]. Because plain fricatives that happen to manifest coarticulatory rounding appear never to be whistled, it is hypothesized that a unique linguopalatal stricture may be the best differentiator of plain and whistled fricatives. These findings relate to the role played by secondary articulations in sound change.