This book addresses issues of authenticity, ecology and evolution in the indigenised varieties of English. It describes Cameroon English within its own natural internal and external ecology, and analyses it as a complete medium of communication that represents a complete sociohistorical community. The framework of filtration processes introduced in the book ushers the study of post-colonial Englishes into the broader linguistic debate about the status of non-native Englishes, making it possible to study them as fruits of given sociohistorical contexts rather than as simple side effects of improper education, faulty second language learning, or non-native deficits in English proficiency.