Aspects of the phonetics and phonology of Southern Sotho /a/

Abstract

Up until now it has been taken for granted that Southern Sotho only has one /a/ phoneme, without any allophonic variation. Barnard and Wissing (2008) indicated the possibility of an opposite situation. In this study we explored this suggestion in detail. We concluded that /a/ is indeed characterized by at least two distinct allophones. Such allophones are ascribed to a process of vowel-to-vowel coarticulation, a specific type of vowel anticipatory assimilation. According to this process, the articulatory features of vowel height and vowel backness of /a/ in the negative formative ha are changed to positions that are closer to that of the mid-high ‘e’ or high ‘i’ of the following syllables, specifically in constructions ha (ke (tlo)) and ha (di), and ha (ba), all followed by a verb. These articulatory features translate to the corresponding acoustic features F2 and F1 respectively. Compared to ‘a’ of ha (ba), taken as the base-line vowel, the differences with respect to both F1 and F2 (and also F2—F1) are statistically significant.