I seriously love this thread!! It made me smile.:P And it doesn't take the whole world to learn it. Martha's Vinyard didn't include the whole world, and there are cultures the world over that have deaf communities that are just like Martha's Vineyard used to be...all people, hearing and deaf, in those communities sign from birth. Bali is one. As small as Bali is, and it certainly isn't industrialized, yet their acceptance of the deaf is more advanced that here.
BTW...the whole world doesn't know English. LOL