A wonderful collection of videos with Plains Indian Sign Language has been put on YouTube by Tommy Foley.

A short ‘teaser’ with subtitles

The videos were recorded in 1930, Browning Montana, when sign talkers from 14 different Plains nations gathered as participants in a conference organized by General Hugh L. Scott for the purpose of demonstrating their use of sign language.

The first four videos (see this playlist) contain material from the participants at the conference themselves: Indians telling stories.

Another six videos are a video version of a dictionary of the language (see this playlist).

Following the 1930 Plains Indian Sign Language Conference, General Scott intended to produce a cinematic dictionary of over thirteen hundred signs. Due to the Great Depression it would have been too difficult to get a second appropriation bill passed through congress to finish the cinematic dictionary. He did manage to get over three hundred signs filmed. (Note from Tommy Foley)

An important documenter of the Plains Indian Sign Language was Col. Garrick Mallery. He wrote ‘Sign Language Among North American Indians Compared With That Among Other People And Deaf-Mutes’ a report for the Smithsonian Insitute which was published in 1881, which is avaliable for free download as an e-book via Project Gutenberg.