Martha's Vineyard Sign Language

Martha's Vineyard Sign Language was a form of sign language that developed in Martha's Vineyard, Massachusetts, because of the extremely high percentage of deaf people living there (1 out of 155, compared to 1 out of 6,000 for the general United States population, with 1 out of 4 people deaf in the Chilmark, Massachusetts neighborhood of Squibnocket).

The sign language originated in Weald, England, where many of the original inhabitants came from: researchers later discovered that some of the early settlers carried a gene which causes deafness. It was combined with French sign language and later with American Sign Language (ASL), though it maintained a number of features that kept it distinct. From the late 1700s to the early twentieth century, virtually everyone on Martha's Vineyard possessed some degree of fluency in the local sign language.

The language was eventually replaced by ASL, and the recurrent deafness finally eliminated as people migrated from the island and new populations moved in.