Martha's Vineyard Sign Language

Martha's Vineyard Sign Language (MVSL) was a village sign language once widely used on the island of Martha's Vineyard off the coast of Massachusetts, U.S., from the early 18th century to the year 1952. It was used by both deaf and hearing people in the community; consequently, deafness did not become a barrier to participation in public life. Martha's Vineyard Sign Language is also notable for the role it played in the development of American Sign Language.

The language was able to thrive on Martha's Vineyard because of the unusually high percentage of deaf islanders and because deafness was a recessive hereditary trait, which meant that almost anyone might have both deaf and hearing siblings. In 1854, when the island's deaf population peaked, the United States national average was one deaf person in 5728, while on Martha's Vineyard it was one in 155. In the town of Chilmark, which had the highest concentration of deaf people on the island, the average was 1 in 25; in a section of Chilmark called Squibnocket, as much as a quarter of the population of 60 was deaf.

Hearing people sometimes signed even when there were no deaf people present: children signed behind a schoolteacher's back; adults signed to one another during church sermons; and farmers signed to their children across a wide field, where the spoken word would not carry.