Colonially-imposed linguistic boundaries have often represented important obstacles to historical and anthropological research in Africa. Even where researchers working in African vernaculars employ data in a transfrontier context, their publications usually appear in only one European language, and are therefore often not accessible to Africans or western researchers unacquainted with that language. The resultant linguistic fragmentation of Africanist publications sometimes leaves the impression of limited sources on a given topic, whereas in fact the relevant sources may be very rich when the writings of two or more national units--often presenting quite different conceptual approaches as well as languages--are drawn on fully.

Some of the most arresting examples of such myopic behavior are evident along Zaire's eastern border with former British administered areas of eastern Africa. T.O. Ranger's valuable account of the Mwana Lesa Watch Tower movement is a case in point. His discussion of Tomo Nyirenda's activities in northern Zambia is detailed and highly revealing. But the Mwana Lesa Movement was also active in the southern pedicule of Zaire, and there are numerous published works (of varying quality) in French on this fascinating example of colonial repression of African religious initiative. Although his account does draw on works in English which are based on (unspecified) Congo materials, only a single francophone source appears in Ranger's otherwise intriguing synthesis.

Farther north, the long border between Zaire and former British-administered areas provides many other examples of similarly narrow linguistic horizons. Little work, for example, has appeared on the translacustrine ties among people living on the lakeshores of the western rift lakes.