Long before American Sign Language (ASL) was developed, the Native tribes of the Great Plains created their own remarkable system of communication—Plains Indian Sign Language (PISL). This language was born out of necessity. Dozens of tribes, such as the Sioux, Cheyenne, Arapaho, Comanche, Kiowa, and Crow, spoke completely different languages. Yet they needed a way to trade, form alliances, share stories, and keep peace. From this need, a universal sign language emerged. ✨ What makes PISL unique?