This book is a documentation of findings from a sociolinguistic investigation of bilingual behaviour in an African cosmopolitan setting where English is spoken as a second language. The author provides interesting insights into the social dynamics of Yoruba - English code-switching and code-mixing as two crucial components of the language contact situation in central Lagos. The book explores the historical and cultural dimensions of the concept of language variation in dissecting the multifarious constituents of bilingual speech across generational boundaries. The book is an invaluable resource material for both teachers and students of English as a second language, as well as a stimulating guide for researchers.