[6] This language was used historically as a lingua franca, notably for trading among tribes; it is still used for story-telling, oratory, various ceremonies, and by deaf people for ordinary daily use.

[7] In 1885, it was estimated that there were over 110,000 "sign-talking Indians", including Blackfoot Confederacy, Cheyenne, Sioux, Kiowa and Arapaho.

However, growing interest and preservation work on Plains Sign Language has increased its use and visibility in the 21st century.

[7] Jeffrey E. Davis, a leading linguist in documentation efforts,[5] hypothesizes that this contact, combined with potential contact with Martha's Vineyard Sign Language (another potential antecedent to ASL) may suggest that ASL descends in part from Plains Sign Language.

Signing may have started in the south of North America, perhaps in northern Mexico or Texas, and only spread into the Plains in recent times, though this suspicion may be an artifact of European observation.

Plains Sign Language spread to the Sauk, Fox, Potawatomi, Cherokee, Chickasaw, Choctaw, and Caddo after their removal to Oklahoma.

Via the Crow, it replaced the divergent Plateau Sign Language[citation needed] among the eastern nations that used it, the Coeur d'Alene, Sanpoil, Okanagan, Thompson, Lakes, Shuswap, and Colville in British Columbia, Washington, and Idaho, with western nations shifting instead to Chinook Jargon.

The various nations with attested use, divided by language family, are: A distinct form is also reported from the Wyandot of Ohio.

In his unpublished dissertation, he developed a notation system and analysed Plains Sign Language as having eighty-two phonemes, which he called kinemes, each being able to be broken down further in terms of features.

[9]: 85 West analyzed Plains Sign Language as having non-isolable phonemes classified as handshapes, directions, referents, motions or motion-patterns, and dynamics.

[18]: 6 There are twelve dynamic phonemes, working similarly to suprasegmentals like stress or tone in that while every sign must be made with some speed or force, only certain ones are marked.

When no stress dynamic is present, motions default to an intermediate force and speed, and tension is irrelevant.

[9]: 96  Preliminary analysis has shown that Plains Sign Language seems to adhere to these conditions, and also favours unmarked handshapes.

Except for the package and in stark contrast to most deaf sign languages, where signs often flow freely into each other, the boundaries of each of these prosodic units are consistently marked with one of three junctures: The hands move partway towards the paragraph-final juncture position but recoil before reaching it.Two variants have the hands clasped near the chest or, if sitting, the palms lightly touched to the thighs, though this variant is rarer.

[18]: 53–56 As Plains Indian Sign Language was widely understood among different tribes, a written, graphic transcription of these signs is known to have functioned as a medium of communication between Native Americans on and off reservations during the period of American colonization, removal, and forced schooling in the late 19th and early 20th centuries.