Tapiete belongs to the well-studied and documented Tupi-Guarani linguistic family. Rodrigues (1984/85) identifies seven groups of languages that form part of the Tupi-Guarani linguistic family. According to this author, the Tapiete belongs to the first one of these groups together with Old Guarana, Mbya, Xeta , Ñandeva (Chiripa), Caiwa, Paraguayan Guarani, Guayaki, and Chiriguano.

The origin of the Tapiete people has been subject to debate. Two hypotheses have been presented. The first one suggests that the Tapiete are Guarani that, after having separated from the original group, kept their language, and acquired the customs of their neighbors, especially Toba Indians (Cardus 1986 in Schmidt 1938). The second hypothesis suggests that the Tapiete Indians are a tribe from the Chaco region which speaks a Tupi-Guarani language. More specifically, they were ‘chiriguanized’ by the Ava-Guarani (commonly known by the term ‘chiriguanos’). On the linguistic level, this suggestion implies that the Tapiete language is the result of the adoption of a Guarani language (i.e. the Ava-Guarani language) by a Chaco indigenous group (Rodrigues 1984/85:42) This last hypothesis has been rejected by the Tapiete themselves.