27,500 (2000 INALI). 7% monolinguals. Original Soyaltepec variety may only be 900, mostly monolingual.
Oaxaca, northwest Tuxtepec district, Soyaltepec municipality, Santa María Jacatepec and San Miguel Soyaltepec towns, Soyaltepec island.
5% intelligibility of Chiquihuitlán [maq].
All ages. Also use Spanish [spa].
Dam built in 1954, resulted in many other Mazatec varieties moving into the municipality. Soyaltepec Island has the least mixture.