The Cheyenne (/ʃaɪˈæn/ shy-AN) are one of the groups of indigenous people of the Great Plains and their language is of the Algonquian language family. The Cheyenne comprise two Native American groups, the Só'taeo'o or Só'taétaneo'o (more commonly spelled as Suhtai or Sutaio) and the Tsétsêhéstâhese (also spelled Tsitsistas). These tribes merged in the early 19th century.