American Sign Language (ASL) is a natural language that serves as the predominant sign language of deaf communities in the United States and most of Anglophone Canada. ASL is a complete and organized visual language that is expressed by employing both manual and nonmanual features. Besides North America, dialects of ASL and ASL-based creoles are used in many countries around the world, including much of West Africa and parts of Southeast Asia. ASL is also widely learned as a second language, serving as a lingua franca. ASL is most closely related to French Sign Language (LSF). It has been proposed that ASL is a creole language of LSF, although ASL shows features atypical of creole languages, such as agglutinative morphology.

Plains Indian Sign Language (PISL), also known as Hand Talk or Plains Sign Language, is an endangered language common to various Plains Nations across what is now central Canada, the central and western United States and northern Mexico. This sign language was used historically as a lingua franca, notably for trading among tribes; it is still used for story-telling, oratory, various ceremonies, and by deaf people for ordinary daily use.