Is language innate, or is it learned? Scientists have been debating the point for as long as we've thought to ask the question. This BBCnews article discusses a find that could help bring us closer to an answer:

A new sign language created over the last 30 years by deaf children in Nicaragua has given experts a unique insight into how languages evolve.

Apparently deaf people in Nicaragua were very isolated until around 1981, when a vocational school for the deaf was opened. The children attending developed their own sign language, without instruction from any adult or outside agency. Like other forms of language, this "new" system holds many things in common with regular languages, notably the ability to break concepts down into "chunks", and then reassemble them into sentences that can convey other meanings.