Wikipedia
The ' Mordvins', also Mordva, Mordvinians, Mordovians (/erźat, /mokšet, /muxşilar, /mordva; for Qaratai: /karatayi), are the members of a people who speak a Mordvinic language of the Uralic language family and live mainly in the Republic of Mordovia and other parts of the middle Volga River region of Russia.
The Mordvins are one of the larger indigenous peoples of Russia. They identify themselves as separate ethnic groups: the Erzya and Moksha, besides the smaller subgroups of the Qaratay, Teryukhan and Tengushev (or Shoksha) Mordvins who have become fully Russified or Turkified during the 19th to 20th centuries. Less than one third of Mordvins live in the autonomous republic of Mordovia; the rest are scattered over the Russian oblasts of Samara, Penza, Orenburg and Nizhny Novgorod, as well as Tatarstan, Chuvashia, Bashkortostan, Central Asia, Siberia, Far East, Kazakhstan, Azerbaijan, Armenia and the United States.
The Erzya Mordvins (, Erzyat; also Erzia, Erza), who speak Erzya, and the Moksha Mordvins (, Mokshet), who speak Moksha, are the two major groups. The Qaratay Mordvins live in the Kama Tamağı District of Tatarstan, and have shifted to speaking Tatar, albeit with a large proportion of Mordvin vocabulary ( substratum). The Teryukhan, living in the Nizhny Novgorod Oblast of Russia, switched to Russian in the 19th century. The Teryukhans recognize the term Mordva as pertaining to themselves, whereas the Qaratay also call themselves Muksha. The Tengushev Mordvins live in southern Mordovia and are a transitional group between Moksha and Erzya.
The western Erzyans are also called Shoksha (or Shoksho). They are isolated from the bulk of the Erzyans, and their dialect/language has been influenced by the Mokshan dialects.