Aspiration of English voiceless stop consonants in Southern Sotho: a case study

Abstract

This article investigates voice onset times (VOT) as produced by Southern Sotho speakers in their own language and in their pronunciation of English. Three levels of L2 proficiency are considered, namely those of Grade 7, Grade 12, and graduated Southern Sotho speakers of English—each group a minimum of five years apart. The purpose is to study the interaction between two similar, yet distinct consonantal systems in the process of language acquisition, viz. aspirated consonants of Southern Sotho and English. Of special theoretical interest is the fact that Southern Sotho possesses a dual system, in which presence or absence of aspiration is phonemic, in contrast with English, where aspiration is phonetically motivated and thus a predictable feature, dependent on factors such as position in a syllable, or of stress. Presence or absence of aspiration is often taken to be a notable trait characterizing the nativeness of second- language accents. The most important findings of this investigation are that VOT values of the three diverse groups do serve as a discriminative factor as long as the data sets are sufficiently large. In such large sets, the results support the general hierarchy for the place of articulation of voiceless aspirated stops in Southern Sotho as well as in the English accent of Southern Sotho speakers. When VOTs per group are considered, the pattern tends to get disturbed. On the grounds of the results, a specific kind of language interference rather than the usual one of negative language transfer is proposed. The theory of lexical frequency turns out not to be able to explain some specific findings, e.g. the behaviour of the bilabial [p^h] in the English productions, especially that of the youngest group of speakers.