Classification
The Mazatecan languages are part of the Oto-Manguean language family and belong to the family's Eastern branch. In that branch, they belong to the Popolocan subgroup together with the Popoloca, Ixcatec and Chocho languages. Brinton was the first to propose a classification of the Mazatec languages, which he correctly grouped with the Zapotec and Mixtec languages. In 1892 he second-guessed his own previous classification and suggested that Mazatec was in fact related to Chiapanec-Mangue and Chibcha.
Early comparative work by Morris Swadesh, Roberto Weitlaner and Stanley Newman laid the foundations for comparative Oto-Manguean studies, and Weitlaner's student María Teresa Fernandez de Miranda was the first to propose reconstruction of the Popolocan languages which while it cited Mazatec data, nonetheless left Mazatecan out of the reconstruction.
Subsequent work by Summer Institute linguist Sarah Gudschinsky gave a full reconstruction first of Proto-Mazatec (Gudschinsky 1956) and then of Proto-Popolocan-Mazatecan (Gudschinsky 1959) (then referred to as Popotecan, a term which didn't catch on).
Read more about this topic: Mazatecan Languages