It is known only through a short list of words and phrases recorded by Father Christoval Romero and given by him to Captain Sebastián Lanchas de Estrada, who included them in the report of his travels of 1768.
Father Romero's word list was discovered in the archives and published, with analysis and commentary, by Rivet (1942), who argued that the language was a member of the Hokan language family.
This claim is considered poor and unconvincing; a critique is given by Poser (1992).
Swadesh (1963) saw connections with Opaye and Chamicura (Maipurean).
However, it is generally considered unclassifiable due to the paucity of data.