Sign languages can evolve from scratch in the space of a generation. (c) Punchstock
The Al-Sayyid Bedouins, (...), have a high rate of congenital deafness. In a population of about 3,500, roughly 150 people are deaf. The community, which was founded about 200 years ago, has developed its own sign language over the past 70 years, with no apparent outside influences. This is the first documented example of a language evolving from scratch in such isolation.