The rise, development and apparent transformation of Sheng from a covert ‘youth’ language into a vernacular of wider use in Kenya within half a century is indeed a fascinating phenomenon. It adds to our understanding of language contact and change, and is linked to the massive demographic transformations that have taken place in post-colonial Kenya. In the new millennium, Sheng has received influences from across the globe, with significant contributions by Africans in the diaspora through internet-based information systems. Sheng is on the rise and increased acceptability will widen its role in all levels of communication, so it is a matter of on-going relevance to study further its impact on the language ecology of Kenya, especially the implications of its entry into domains previously restricted to English and Swahili. What is Sheng's future as its role in politics, print and broadcast media continues to grow at the current fast pace? What is the long-term impact on the two official languages – English and Swahili – and on the rest of Kenyan languages in general? Should Sheng have a place in the repertoire of existing (and contested) Kenyan vernacular languages? Is it possible to ‘eradicate’ Sheng, in response to a section of public opinion? Sheng is indisputably the dominant vernacular speech of the low-income estates of Nairobi (mitaa), but speakers also adjust their speech (‘Kenyanese’) according to social relations they share with their interlocutors. In trade and industry, it is the vernacular of the urban proletariat (youths, adult men and women) working in the ‘informal sector’ of the jua kali industry, street hawkers, mitumba sellers and market traders, and of course matatu public transport operators.

Sheng richly adds to the existing repertoires of Swahili broadly, and to Kenyanese in particular – the spectrum of speech codes with which Kenyans navigate around a complex and stratified multilingual ecology. Sheng innovations and its ‘non-standard’ features have gained widespread use and acceptability as normal features of Kenyan Swahili (KS), thus marking the addition of a new variety to the Swahili macrolanguage. The popular view of Sheng remains that of an urban youth peer language – lugha ya mabeste or the language of ‘besties’ (friends) of the lower socio-economic classes – but it is no longer restricted to that single demographic bracket of the population.