The linguistic and genetic landscape of southern Africa.

The present-day diversity of southern African populations was shaped by the confluence of three major pre-historic settlement layers associated with distinct linguistic strata: i) an early occupation by foragers speaking languages of the Kx'a and Tuu families; ii) a Late Stone Age migration of pre-Bantu pastoralists from eastern Africa associated with Khoe-Kwadi languages; iii) the Iron Age expansion of Bantu-speaking farmers from West-Central Africa who reached southern Africa from the western and eastern part of the continent. Uniting data and methodologies from linguistics and genetics, we review evidence for the origins, migration routes and internal diversification patterns of all three layers. By examining the impact of admixture and sex-biased forms of interaction, we show that southern Africa can be characterized as a zone of high contact between foraging and food-producing communities, involving both egalitarian interactions and socially stratified relationships. A special focus on modern groups speaking languages of the Khoe-Kwadi family further reveals how contact and admixture led to the generation of new ethnic identities whose diverse subsistence patterns and cultural practices have long puzzled scholars from various disciplines.