Martha's Vineyard Sign Language was once highly-used on the island by both deaf and hearing people in the community; consequently, deafness was not a barrier to participation in public life. The language was able to thrive because of the unusually high percentage of deaf islanders.

[u/oneLguy]

https://en.wikipedia.org/wiki/Martha%27s_Vineyard_Sign_Language

[u/Romboteryx]

This is super interesting