Martha's Vineyard Sign Language
Martha's Vineyard Sign Language (MVSL) was a village sign language that was once widely used on the island of Martha's Vineyard, United States, from the early 18th century to 1952. It was used by both deaf and hearing people in the community; consequently, deafness was not a barrier to participation in public life.
Source: Wikipedia — Martha's Vineyard Sign Language (CC BY-SA 4.0)