How far south is Didxsaj spoken?
Mitla Zapotec: Mitla Zapotec, or "Didxsaj," is an Oto-Manguean language of Oaxaca, Mexico. Oto-Manguean languages:  All of the Oto-Manguean languages that are now spoken are indigenous to Mexico, but the Manguean branch of the family, which is now extinct, was spoken as far south as Nicaragua and Costa Rica.
Nicaragua and Costa Rica