Mentawai (also known as Mentawei and Mentawi) are the native people of the Mentawai Islands, province West Sumatra, Indonesia. The Mentawai Islands are a chain of about seventy islands and islets off the western coast of Sumatra in Indonesia. West Sumatra ( Indonesian: Sumatera Barat, abbreviated to Sumbar) is a province of Indonesia. The Republic of Indonesia ( (Republik Indonesia is a Country in Southeast Asia. They live a semi-nomadic hunter - gatherer lifestyle in the coastal and rainforest environments of the islands. The Mentawai population is estimated to be about 64,000. The Mentawai language belongs to the Austronesian language family. The Mentawai language is an Austronesian language, spoken by the Mentawai -people of the Mentawai Islands, West Sumatra.