A Chiwere speaker is someone who speaks a language belonging to the Siouan language family. The three crossword solutions for this term are Otoe, Iowas, and Oto. Otoe is a Native American tribe that is part of the Great Plains Indians. They are closely related to the Iowas, another Native American tribe that is also part of the Great Plains Indians. Oto is a language spoken by the Otoe and Iowas tribes.