 In 1880, Dorsey returned to Washington to work with the BAE at the Smithsonian as a specialist in Siouan languages, a position he held for the rest of his life.Dorsey later did field work with the Siouan-speaking Tutelo in Canada, the Biloxi in Louisiana, and the Quapaw in Oklahoma.In addition, he studied several tribes along the Oregon coast, where he compiled materials on the Athabaskan (also called Dene), Coosan, Takilman, and Yakonan language families or "stocks", some of which were spoken by small groups of people.