Edwin James Benson ((1931-10-23)October 23, 1931 – (2016-12-09)December 9, 2016; Ma-doke-wa-des-she, modern Mandan orthography: Wéroke Wáatashe, Iron Bison[1]) was a Native American educator and the last native speaker of the Mandan language.

When the Garrison Dam was built, Benson and his family were relocated to Twin Buttes, North Dakota.

He taught Mandan at Twin Buttes Elementary School, and was awarded an honorary doctorate from the University of North Dakota in 2009.

[2][3] He was involved in efforts to teach the basics of Mandan to youth.

[4] The documentary To Save a Language (2020) showed the efforts of the Estonian linguist Indrek Park [et] who tried to learn and save the Mandan language.