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 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 played a role 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.

Origins
The ancestry of most of the deaf population of Martha's Vineyard can be traced back to a forested area in the south of England known as the Weald—specifically the part of the Weald in the county of Kent. Martha's Vineyard Sign Language may be descended from a hypothesized sign language of that area in the 16th century, now referred to as Old Kent Sign Language. Families from a puritan community in the Kentish Weald emigrated to the Massachusetts Bay Colony area of the United States in the early 17th century, many of their descendants later settling on Martha's Vineyard. The first deaf person known to have settled there was Jonathan Lambert, a carpenter and farmer, who moved there with his hearing wife in 1694. By 1710, the migration had virtually ceased, and the endogamous community that was created contained a high incidence of hereditary deafness that would persist for over 200 years.

By the 18th century there was a distinct Chilmark Sign Language, which was later (19th century) influenced by French Sign Language, forming Martha's Vineyard Sign Language (19th and 20th centuries). From the late 18th to the early 20th century, virtually everyone on Martha's Vineyard possessed some degree of fluency in the local sign language.

Deaf migration to the mainland
In the early 19th century, a new educational philosophy began to emerge on the mainland, and the country's first school for the deaf opened in 1817 in Hartford, Connecticut (now called the American School for the Deaf). Many of the deaf children of Martha's Vineyard enrolled there, taking their sign language with them. The language of the teachers was French Sign Language, and many of the other deaf students used their own home sign systems. This school became known as the birthplace of the deaf community in the U.S., and the different sign systems used there, including MVSL, merged to become American Sign Language or ASL—now one of the largest community languages in the country.

As more deaf people remained on the mainland, and others who returned brought with them deaf spouses they met there (whose hearing loss may not have been due to the same hereditary cause), the line of hereditary deafness began to diminish. As the 20th century came to a turn, the previously isolated community of fishers and farmers began to see the influx of tourists that would become a mainstay in the island economy. The jobs in tourism were not as deaf-friendly as fishing and farming had been. Further, as intermarriage and migration joined the people of Martha's Vineyard to the mainland, the island community more and more resembled the wider community there.

The last deaf person born into the island's sign language tradition, Katie West, died in 1952. A few elderly residents were able to recall MVSL as recently as the 1980s when research into the language began. Indeed, when Oliver Sacks subsequently visited the island after reading a book on the subject, he noted that a group of elderly islanders talking together dropped briefly into sign language then back into speech.