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 ownlanguage and in their pronunciation of English. Three levels of L2 profi ciency are considered, namelythose of Grade 7, Grade 12, and graduated Southern Sotho speakers of English – each group a minimumof fi ve years apart. The purpose is to study the interaction between two similar, yet distinct consonantalsystems 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 presenceor absence of aspiration is phonemic, in contrast with English, where aspiration is phonetically motivatedand thus a predictable feature, dependent on factors such as position in a syllable, or of stress. Presenceor absence of aspiration is often taken to be a notable trait characterizing the nativeness of secondlanguageaccents. The most important fi ndings of this investigation are that VOT values of the threediverse groups do serve as a discriminative factor as long as the data sets are suffi ciently large. In suchlarge sets, the results support the general hierarchy for the place of articulation of voiceless aspiratedstops in Southern Sotho as well as in the English accent of Southern Sotho speakers. When VOTs pergroup are considered, the pattern tends to get disturbed. On the grounds of the results, a specifi c kindof language interference rather than the usual one of negative language transfer is proposed. The theoryof lexical frequency turns out not to be able to explain some specific findings, e.g. the behaviour of thebilabial [p^h] in the English productions, especially that of the youngest group of speakers.