Her work on Native American culture of fluency in both the Yankton and Lakota dialects of Sioux, both of which she had used as a child, as well as the eastern language of Sioux.

Her linguistic skills and her intimate knowledge of traditional and Christianised Sioux culture, together with her deep dedication both toNative American culture and to scholarship, allowed Deloria to carry out significant, often ground-breaking work in anthropology and ethnology, as well as to produce translations in to English of historical and scholarly texts in Sioux.

Deloria won the Indian Achievement Award in 1943, and was the recipient of grants from the Wenner-Gren Foundation (1948) and the National Science Foundation (1960s).