San Sebastián del Monte Mixtec (SSM) (ISO:mks), also known as Tò’on Ndà’vi, is a language of the Mixtecan family, Otomanguean stock (Rensch 1976). The Mixtecan language family consists of Mixtec, Cuicatec and Trique, though Mixtec and Cuicatec are part of the same subgroup, also called Mixtecan (Josserand 1983: 99–101). SSM is part of the Mixteca Baja region of Oaxaca (Josserand 1983: 107). San Sebastián del Monte is a town in the Santo Domingo Tonalá municipality of Oaxaca State, Mexico, in the district of Huajuapan de León, 45 km southwest of Huajuapan de León (see Figure 1), with a population of approximately 2000 people (latitude: 17.677778, longitude: −98.021944).