Plains Indian Sign Language
"The Whites have had the power given them by the Great Spirit to read and write, and convey information in this way. He gave us the power to talk with our hands and arms, and send information with the mirror, blanket and pony far away, and when we meet with Indians who have a different spoken language from ours, we can talk to them in signs." - Chief Iron Hawk, Sioux Nation.
North American Indians have developed and employed signed languages for thousands of years to communicate with one another between tribes which communicated different speech languages in the Great Plains region of North America. There is a number of records written since the 16th century by early explorers who had encountered the Plains Indians and observed how they communicated easily and freely with one another in signed language.
"I have met Comanches, Kiowas, Apaches, Caddos, Snakes, Crows, Pawnees, Osages, Mescalero Apaches, Arickarees, Gros Ventres, Nez Perces, Cherokees, Choctaws, Chickasaws, Sacs and Foxes, Pottawattomies, and other tribes whose vocal languages, like those of the named tribes we did not understand, and we communicated freely in sign language." - Chief Little Raven, Arapahoe.
The YouTube video below shows an example of what Plains Indian Sign Language looked like in 1930 during the Indian Sign Language Conference in Browning, Montana, where Native American signers from 14 different Plains tribes participated in. The conference was sponsored by the U.S. government to demonstrate the Plains signed language and to preserve this ancient intertribal language by recording it on film.
References / Resources
"Plains Indian Sign Language: A Memorial to the Conference." http://ublib.buffalo.edu/libraries/e-resources/ebooks/records/7132.html
"Indian Sign Language." http://www.inquiry.net/outdoor/native/sign/index.htm (image-based dictionary)
"Native American Sign Language." http://www.comanchelodge.com/sign-language.html (word-based dictionary)