This article is concerned with language alternation between Twi and English in informal conversation . Twi is the most widely spoken indigenous language of Ghana, also used in the broadcast media, especially radio; English, the former colonial language, is the official language, and the main language of the education system and print media. However, English is now gradually encroaching on domestic and informal domains, and younger urban speakers are increasingly shifting towards English as a first language . Participants in the conversations examined here were of different generations and educational backgrounds . Analysis was approached from both a structural and a sociolinguistic perspective . The data reveal developing patterns in the contact between the grammars and lexicons of Twi and English. They also reflect associations and values attached to Twi and English respectively, and to codeswitching as a communicative mode of everyday interaction in Ghanaian society .