By the 1900s, the use of Indian Sign Language was greatly diminished and appeared endangered. Recognizing the endangered status of Indian Sign Language, General Hugh L. Scott led the preservation effort until his death in 1934. Scott is a notable historical figure, and his extensive papers from collections within the and in Washington, D.C. In 1930, through no less than an Act of the US Congress, the Smithsonian National Museum of Natural History and other governmental agencies collaborated to produce a film and dictionary project for the "Preservation of Indian Sign Language." General Hugh L. Scott had lobbied Congress for support and directed the project that led to The Indian Sign Language Grand Council that was filmed September 4-6, 1930, in Browning, Montana. The Council was co-hosted by the Blackfeet Nation
This event was the largest intertribal meeting of Indian chiefs, elders, medicine men, and other representatives ever filmed. There were eighteen official participants, including representatives from a dozen different tribes and language groups from the Plains, Plateau, and Basin cultural areas. A permanent monument to the Indian Sign Language Council signifying the importance of this gathering was established at the conference site, and each of the council members had their footprints placed in bronze as a part of the monument. On this site was eventually constructed the Museum of the Plains Indian.