How far south is Didxsaj spoken?
Nicaragua and Costa Rica
Title: Oto-Manguean languages
Passage: Oto-Manguean languages (also Otomanguean) are a large family comprising several subfamilies of indigenous languages of the Americas.  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.  Oto-Manguean is widely viewed as a proven language family.  However, this status has been recently challenged (Brown 2015).
Title: Mitla Zapotec
Passage: Mitla Zapotec, or "Didxsaj," is an Oto-Manguean language of Oaxaca, Mexico.
Title: Ventureño language
Passage: Ventureño is a member of the extinct Chumashan languages, a group of Native American languages previously spoken by the Chumash people along the coastal areas of Southern California from as far north as San Luis Obispo to as far south as Malibu.  Ventureño was spoken from as far north as present-day Ventura to as far south as present-day Malibu and the Simi Hills, California.  Dialects probably also included Castac and Alliklik (Campbell 1997:126).
Oto-Manguean languages Mitla Zapotec