The purpose of this paper is to foreground the extent to which the English language has eroded the originality and purity of the Yoruba language. The main focus will be on code-switching practices, which I believe to be detrimental to Yoruba in the long run. Although linguists have long proposed a ‘leave-your-language-alone’ attitude (see Hall, 1950), there is little doubt that the effects of first British colonization and then globalization have changed the linguistic ecology of Africa. Few sociolinguists would deny that a people's language is a symbol of their identity and culture. In an important textbook in the field, Holmes (1992: 70) confirms that ‘Language is an important component of identity and culture for many groups, maintaining their distinct identity and culture is usually important to … self esteem.’ What are we then to make of the extensive code-switching that I will be documenting in this article? Linguists' tolerance has certainly extended to code-switching studies in Africa, from which much important data has been drawn. The main scholar in this area is Carol Myers-Scotton, whose two books on code-switching (1993a,b) were based primarily on her research in Africa and remain central to the field internationally. Scholars like Coupland and Jaworski (1997) propose that the use of mixed speech in a conversation is not necessarily a language defect but a sign of flexibility and creativity. Understanding the social, psycholinguistic and syntactic motivations for switching is one thing, but the applied linguist and educationist also has to ask serious questions about what this means for the future of local languages heavily implicated in code-switching.