The languages-of Buka and northern Bougainville are Austronesian. Most of the southern Bougainville languages are associated with earlier settlers. Polynesian languages are spoken on the Takuu and Nukumanu islands. Tok Pisin is the main second language.
Most people live in central villages, with second houses near their crops.
Sweet potatoes and fish are the main foods. Taro is the second starch food in the north-west, yams in the southeast. A wide variety of traditional and introduced foods are grown. In swamp areas, sago is an emergency food. Most people base clan membership and inheritance rights on their mother's family line.