NICARAGUAN SIGN LANGUAGE.

A sign language developed by children at a school in Managua, Nicaragua, over the last 35 years and studied by a Barnard team led by Ann Senghas has been in the news recently (Barnard press release, BBC News, New Scientist, NPR audio; also, from five years ago, a long NY Times Magazine story with photos), and a number of people have sent me links (thanks Bonnie, Eve, and whoever I’m forgetting!). The Wikipedia entry has a good summary of events:

Following the 1979 Sandinista revolution, the newly installed Nicaraguan Government had hundreds of deaf students enrolled in two Managua schools. Initially, the education officials adopted “finger spelling,” using simple signs to limn the alphabets of spoken languages. The result was a complete failure, because most students did not even grasp the concept of words, never having been exposed either to spoken or to written language. The children remained linguistically disconnected from their teachers.
Initially, the students could only use crude gestural signs developed within their own families, but once the students were placed together, they began to build on one another’s signs. While the inexperienced teachers found it hard to understand their students, the children had no problem communicating with each other. A new language had begun to bloom. Within just a few generations, a mature language with rules and grammar was born.

The Sandinista officials asked for help from outside scholars. After the linguists finally decoded the children’s creation, Nicaraguan Sign Language became a classical case of modern linguistics. Some linguists see what happened in Managua as proof that language acquisition is hard-wired inside the human brain. “The Nicaraguan case is absolutely unique in history,” Steven Pinker, author of The Language Instinct, maintains. “We’ve been able to see how it is that children — not adults — generate language, and we have been able to record it happening in great scientific detail. And it’s the first and only time that we’ve actually seen a language being created out of thin air.”
In order to protect the language, some researchers are interested in restricting access of these young NSL users to other forms of sign language (e.g. American Sign Language). Others argue that this is an unethical restriction of their freedom of movement.

I don’t have anything in particular to say about this other than that it’s extremely interesting, but you can find a discussion at MetaFilter (as well as a brief but intense complaint about the BBC story at Language Geek; why hasn’t Language Log weighed in?).
Update. The Sept. 21 Science section of the NY Times has a good summary by Nicholas Wade (sorry, I can’t seem to get a blogsafe link, so it will expire in a week):

The children have been studied principally by Dr. Judy Kegl, a linguist at the University of Southern Maine, and by Dr. Ann Senghas, a cognitive scientist at Columbia University. In the latest study, published in the current issue of Science, Dr. Senghas shows that the younger children have now decomposed certain gestures into smaller component signs. A hearing person asked to mime a standard story about a cat waddling down a street will make a single gesture, a downward spiral motion of the hand. But the deaf children have developed two different signs to use in its place. They first sign a circle for the rolling motion and then a straight line for the direction of movement.
This requires more signing, but the two signs can be used in combination with others to express different concepts. The development is of interest to linguists because it captures a principal quality of human language – discrete elements usable in different combinations – in contrast to the one sound, one meaning of animal communication. “The regularity she documents here – mapping discrete aspects of the world onto discrete word choices – is one of the most distinctive properties of human language,” said Dr. Steven Pinker, a cognitive scientist at Harvard.
When people with no common language are thrown into contact, they often develop an ad hoc language known to linguists as a pidgin, usually derived from one of the parent languages. Pidgins are rudimentary systems with minimal grammar and utterances of the “Me Tarzan, you Jane” variety. But in a generation or two the pidgins acquire grammar and somehow become upgraded into what linguists call creoles.
Though many new languages have been created by the pidgin-creole route, the Nicaraguan situation is unique, Dr. Senghas said, because its starting point was not a complex language but ordinary gestures. From this raw material, the deaf children appear to be spontaneously fabricating the elements of language. Sign languages can possess all the properties of language, including grammar, and differ only in conveying meaning by signs instead of speech.
Until now, children’s specific contribution to language has been hard to define because they end up speaking like their parents. By inventing a new language from scratch, the Nicaraguan children afford linguists the chance to identify children’s role in language creation. Dr. Senghas’s work shows “that children can give the language certain regularities instead of merely extracting them” from their parents’ speech, Dr. Pinker said…
Though there are many creoles, the transition from pidgin to creole has rarely, if ever, been captured in real time, though it has been reconstructed to some extent by interviewing older people. The Nicaraguan children are a living laboratory of language generation. Dr. Senghas, who has been visiting their school every year since 1990, said she had noticed how the signs for numbers have developed. Originally the children represented “20” by flicking the fingers of both hands in the air twice. But this cumbersome sign has been replaced with a form that can now be signed with one hand. The children don’t care that the new sign doesn’t look like a 20, Dr. Senghas said; they just want a symbol that can be signed fast.