Wikipedia
The Nyishi tribe is one of the principal inhabitants of Arunachal Pradesh in north-eastern India. Nyi refers to "a man" and the word shi denotes "a being", which collectively means a civilized human being. They are spread across six districts of Arunachal Pradesh viz., Papum Pare, part of Lower Subansiri, Kurung Kumey, East Kameng, parts of Upper Subansiri, the recently created district Kra Dadi and are also found in the Sonitpur and North Lakhimpur districts of the neighbouring state of Assam.
Their population of around 300,000 makes them the most populous tribe of Arunachal Pradesh, closely followed by the combined tribes of the Adis and the Galos who were the most populous in the 2001 census. The Nyishi language belongs to the Sino-Tibetan family, however, the origin is disputed.
Polygyny is prevalent among the Nyishi. It signifies one's social status and economical stability and also proves handy during hard times like clan wars or social huntings and other social activities. This institution, however is being challenged especially with the trend towards modernization and also with the spread of Christianity. They trace their descent patrilineally and are divided into several clans.