The name of the place is Martha's Vineyard. In the 18th and 19th centuries, a high prevalence of hereditary deafness on the island led to a unique sign language known as Martha's Vineyard Sign Language (MVSL). The high proportion of deaf individuals in Martha's Vineyard resulted in most community members being able to communicate using sign language, making it a place where almost everybody knew sign language.
The place you are referring to is Martha's Vineyard, an island located off the coast of Massachusetts in the United States. On Martha's Vineyard in the 18th and 19th centuries, a high prevalence of hereditary deafness led to a unique situation where both deaf and hearing individuals communicated using Martha's Vineyard Sign Language (MVSL). This allowed nearly everyone on the island to be familiar with sign language, making it commonplace in the community.
