From an AP review:
"Talking Hands: What Sign Language Reveals About the Mind", by Margalit Fox: It sounds like a curious fairy-tale â€” a signed language created out of thin air, spoken in a remote desert village by hearing and deaf alike and witnessed by few outsiders.
Yet Al-Sayyid is no mirage but rather an astonishing true story engrossingly told by Margalit Fox of her journey to this remarkable signing Brigadoon.
Here's the Amazon link:
Talking Hands: What Sign Language Reveals About the Mind
And here's Wikipedia.