An original Pygmy language has been postulated for at least some Pygmy groups. Merritt Ruhlen writes that "African Pygmies speak languages belonging to either to the Nilo-Saharan or Niger–Kordofanian families. It is assumed that Pygmies once spoke their own language(s), but that, through living in symbiosis with other Africans, in prehistorical times, they adopted languages belonging to these two families."[3] However, the only evidence that such languages existed is Mbenga forest vocabulary shared by the neighboring Ubangian-speaking Baka and Bantu-speaking Aka (there is no such common Mbuti vocabulary); if this does represent a common ancestral language rather than borrowing, the speakers may well not have been specifically Pygmies, but instead another of the several potential language isolates of (former) hunter-gatherer populations that ring the rainforest.[4]
A commonly held belief is that African Pygmies are the direct descendants of the Late Stone Age hunter-gatherer peoples of the central African rainforest, who were partially absorbed or displaced by later immigration of agricultural peoples, and adopted their Central Sudanic, Ubangian, and Bantu languages. This view has no archaeological support, and ambiguous support from genetics and linguistics.[5][6][7]
Some 30% of the Aka language is not Bantu, and a similar percentage of the Baka language is not Ubangian. Much of this vocabulary is botanical, deals with honey collecting, or is otherwise specialized for the forest and is shared between the two western Pygmy groups. It has been proposed that this is the remnant of an independent western Pygmy (Mbenga or "Baaka") language. However, this type of vocabulary is subject to widespread borrowing among the Pygmies and neighboring peoples, and the "Baaka" language is only reconstructed to the 15th century, long after the arrival of Bantu and Ubangian peoples to the region.[8]