Emergent tonogenesis in Afrikaans

Afrikaans is usually described as having a contrast between prevoiced and voiceless unaspirated plosives ([b]-[p], [t]-[d]). This study documents an ongoing change in the pre-vocalic realization of the contrast. Preliminary data from five speakers show that all speakers produce some phonologically voiced plosives without prevoicing, with frequency of devoicing ranging from 30% to 85% across speakers. This devoicing is nearly categorical: VOTs of devoiced plosives average 12 ms and those of phonologically voiceless plosives average 17 ms. (By comparison, VOTs of voiced plosives average around Ő130 ms.) The contrast appears to be preserved in the F0 contour of the following vowel, which is 50 to 100 Hz lower (depending on the speaker) after phonologically voiced than after phonologically voiceless plosives. The F0 difference continues through at least 70% of the vowel. However, post-plosive F0 variation is not contingent on devoicing, e.g., F0 contours after phonological /b/ are the same regardless of whether the production is [p] or [b]. In these preliminary data, the magnitude of the F0 difference is linked to speaker age, with younger speakers showing a larger difference. Data from a larger group of speakers are being analyzed and will be presented.