The indigenous people of Bougainville are Melanesian. They speak 19 different languages. Many of these languages are closely related in structure. Each language group tends to be concentrated in one relatively compact area separated from the other groups by tracts of unoccupied land. The number of people speaking a particular language varies considerably with some of the smaller groups having less than 200 and the largest over 12,000 speakers.

Land in most cultures passes to the next generation through the mother's family line. Inheritance is matrilineal.

Most of the village people on Bougainville grow their own food using a traditional system of bush fallow cultivation. The average area of land used for gardening is around 0.1 to 0.2 hectares per head per year. Sweet potato, taro and yam are grown and are the main staple foods with sweet potato being the most widely distributed. Crops, such as sugar cane, pawpaw, bananas, breadfruit and coconuts are also an import part of the village diet. Many families keep pigs and chickens and occasionally supplement their diet by hunting and fishing. Introduced vegetables, including tomatoes, corn and beans are mainly grown as a cash crop.