The language is divided into many dialects, or varieties, some of which are not mutually intelligible. The western dialects spoken in Huautla de Jiménez, and San Mateo Huautla, Santa María Jiotes, Eloxochitlán, Tecóatl, Ayautla, and Coatzospan are often referred to as Highland Mazatec. The North Eastern dialects spoken in San Miguel Huautla, Jalapa de Díaz, Mazatlán de Flores, San Pedro Ixcatlán, and San Miguel Soyaltepec are referred to as Lowland Mazatec. The Highland and Lowland dialects differ by a number of sound changes shared by each of the groups, particularly sound changes affecting the proto-Mazatecan phoneme .