http://www.ethnicgroupsphilippines.com/people/ethnic-groups-in-the-philippines/alangan/
Alangan
  The eight indigenous tribes of Mindoro have known no other home since prehistory, although their ancestors probably migrated from Indonesia. (The seventh-largest island in the Philippines, Mindoro is part of the MIMAROPA Region and is divided into two provinces, Oriental Mindoro and Occidental Mindoro.) The tribes, which are referred to by the general term "Mangyan," comprise the Alangan, Bangon, Buhid, Hanunoo, Iraya, Ratagnon, Tadyawan, and Tawbuid. The Mangyan population in the Philippines is over 100,000, and the great majority have grown roots in Mindoro.
  The Alangan Mangyans inhabit a wide area around Mt. Halcon, northern Mindoro Island. Some Alangans can be found in the Lantuyan and Paitan settlements near the midway point of the Dulangan River.
  The Alangan are of medium build. They have round faces, straight and long hair, and dark complexion. Their teeth are often black from chewing betel nuts. The Alangan economy is based primarily on upland agriculture or the kaingin system (slash-and-burn method). Alangans make new swidden sites every year or two.
Sources:
Mindoro.net, http://www.imindoro.net/
The Mangyan Tribes in Mindoro, http://phch.eccmanila.org/
Ethnologue,www.ethnologue.com