The concept of the linguistic domain is an old one which refers to areas of use of a language, an area of human activity in which one particular speech variety or a combination of several varieties is regularly used (Fishman 1972). In this framework, the choice of language during an interaction is related to roles (e.g. teacher–student, among peer friends), place (e.g. at home, in the street, classroom or school playground), and topic of conversation (e.g. business, family affairs, politics). There are reservations about a concept of rigid ‘domains’ or spheres of language use, but it is still useful as an idealized construct for the purposes of establishing parameters of language practices. The languages of formal and informal domains have always been starkly demarcated in Kenya: English is the language of mainstream print media, international business, higher education and government at the policy-making level, including parliamentary debates. Kenyan Swahili (KS) is the ‘national’ language (of the masses, of popular expression and social solidarity), and in lower level commercial activity and inter-ethnic social interaction and communication. Its standard variety (SS) is the language of school textbooks, news broadcasts and public information, and co-official with English since 2010. The rest of Kenya's 60 odd languages and dialects in vernacular forms are used in situations in which they dominate within their respective communities, in relatively more linguistically homogenous rural areas, or in some urban homesteads. Indigenous languages of Kenya have received a generous boost and rejuvenation since the 1990s when they entered with vigour into media broadcasting on both radio and television. They have created a vibrant industry which provides employment to journalists, newscasters, translators, administrators and infrastructure maintenance workers. It also encourages the development of those languages as their utility enters financially rewarding domains of the linguistic marketplace. It has also made individual Kenyan languages more familiar to citizens of other communities, and of course, they now receive even greater mutual influences due to their greater contact with Swahili, English and other indigenous languages.

More recently, Sheng has found its way into the media, creative and entertainment industries. Its role in these domains of mass media, and the sheer weight of its numbers of users, has begun to influence the speech habits of the rest of the Kenyan population.