The geographic and genetic distribution of the labial flap

This paper documents the geographic and genetic distributions of the labial flap. The flap is an areal feature, concentrated in northcentral Africa, but it is also attested in southeastern Africa and Indonesia. It is found in three of the four major African language families, but it likely cannot be traced back to the proto language of any of these families. It is most widely attested in the Adamawa-Ubangi subgroup of Niger-Congo. We endeavored to obtain a complete sample of the languages in which the sound is attested in order to ensure the accuracy of our typological claims.