This RAPID project will create an accessible, annotated video database for five endangered varieties of Plains Indian Sign Language (PISL) that have received little attention in linguistic research. The database and PISL documentation constitute an important intellectual contribution to academic fields including linguistics, education, history, and sign language studies, while also making a cultural contribution to Native peoples. The main output of the project is a video dictionary to be maintained by the University of Arizona. Its functionality will support comparative analysis between PISL types and with other sign languages. The dataset of PISL lexicons and videos will be shared with the tribes and available to scholars in American Indian studies, linguistics, anthropology, and Indigenous education. It will also be distributed to tribes to be used as educational material in a variety of schools and settings across the nation. The project will involve documentation of tribal signs through the development of a video dictionary/database. Researchers will compare older written documentation and dictionaries from 1880 and 1929 with current signs. Tribal consultants from PISL communities will serve as signers for the database. The database will be annotated and searchable by (a) phonological parameter identifiers, (b) etymological descriptions with the meaning of the signs, and (c) cultural context based on the lives of Plains Indians/Indigenous people. The research team's comparative study of these signs as presented visually and converted from older written dictionaries into a modern digital archive will support the identification of similarities and differences among historical and contemporary signs. Many tribes have shared signs due to intertribal marriages and previous lingua franca use across the Plains region. This project will enable the ability to specify different dialects among these tribes, making this work a direct contribution to new knowledge and an important resource for these tribal communities. The master database will include signs from seven tribes (a single combined dictionary) and will include a dialect filter specifically for Kiowa signs in a second copy of the original database, leading to the production of a Kiowa Sign Language-specific dictionary. This will serve as a model and build capacity for future work by creating a larger database from which dictionaries for individual tribes can be derived. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.