This paper presents information on the regional characteristics of two of South Africa's five major varieties of English: viz. those of its Coloured and Indian communities in five cities: Johannesburg, Cape Town, Durban, Port Elizabeth, and Kimberley. It proposes that as far as the variable (t) is concerned, and by extension (d), these two “interior” social groupings show regional variation of a more robust kind than that of the Black majority and formerly politically dominant White group (the “exterior” groups). The paper describes the relationship between the two interior groups, showing considerable similarities between them for the variable (t), which has two main stop variants, an alveolar and a more fronted (or dental) one. Parallel developments are outlined for (th) (or /θ/ in IPA terms) by a study of word list style, showing similarities between the two groups in four of the cities. These linguistic features are assessed against outsiders' and local speakers' attitudes to and beliefs about their varieties. Finally, the paper considers the origins of the fronted variant, assessing whether it is a spontaneous development or a contact feature associated with Afrikaans-English bilinguals of varied backgrounds. It concludes that while multiple substrate influences are at work, the most likely source is from 17th- and 18th-century Malay and related languages, showing a double substratum, first into Afrikaans, then into English, without a significant period of Malay-English bilingualism.