Members and descendants of the Sisseton Wahpeton Dakota Oyate, a division of the Great Sioux Nation, live east of the Missouri River, mostly in North and South Dakota, and speak the Dakota dialect. As the population of native speakers ages, younger generations breathe new life into study of the language. In college courses, community education classes, and study teams, learners of all ages practice speaking and writing at the same time that they come to understand the storied history of this significant Native American group.

Nicolette Knudson and Jody Snow, students of the...