Lame Deer is a census-designated place (CDP) in Rosebud County, Montana, United States. The community is named after Miniconjou Lakota chief Lame Deer, who was killed by the U.S. Army in 1877 under a flag of truce south of the town. It was the site of a trading post from the late 1870s.

The Cheyenne language, is the Native American language spoken by the Cheyenne people, predominantly in present-day Montana and Oklahoma, in the United States. It is part of the Algonquian language family. Like all other Algonquian languages, it has complex agglutinative polysynthetic morphology. This language is considered endangered, at different levels, in both states.