At a school in Managua, Nicaragua, deaf children are speaking a new language entirely their own, which nonetheless has remarkable similarities to the world's other languages. Researchers studying these similarities suggest this week in Science that, in fact, children give language its most fundamental, universal features just by the way they learn it.
As varied as they may sound to the untrained ear, all languages share certain basic traits that have been the subject of debate for decades.
While some researchers have argued that these traits come hard-wired in the human brain, others have argued that they developed gradually over generations through experimentation and improvement. In contrast, the new study suggests that the source of these similarities is the way languages are learned.
Ann Senghas of Barnard College of Columbia University and her colleagues propose that even if children aren't born with a "blueprint" for language (as Noam Chomsky, for example, has argued), their brains do use a specific approach to learning that can turn a simple communication system into a true language in a surprisingly short period of time.
The researchers compared the ways that deaf children and adults used Nicaraguan Sign Language (NSL) to tell a story. The signers had learned the language at different stages of its brief history.
While the oldest signers described actions using pantomime-like gestures, the younger generations carved the gestures into simpler, basic words, following rules fundamental to all languages.
The authors suggest that as subsequent groups of children have learned NSL, they have, all on their own, turned what was once more like gesture into a true language. Their study appears in the 17 September 2004 issue of the journal Science, published by AAAS, the nonprofit science society.
"We're seeing evolution in action, but what's evolving here isn't an organism. It's a language system," Senghas said.
"Languages essentially 'reproduce' when they are passed from one mind to the next -- that is, when they are learned by a new child. That means the moment of learning is potentially a very powerful moment, an opportunity for shaping and restructuring," she said.
But is it powerful enough to create a whole new language from raw materials such as gestures? According to Senghas and her colleagues, the Nicaraguan case shows that it is.
Senghas' coauthors are Sotaro Kita of the University of Bristol in England and Aslý Özyürek of Nijmegen University and Max Planck Institute for Psycholinguistics in Nijmegen, The Netherlands and of Koç University in Istanbul, Turkey.
Before the 1970s, most deaf people in Nicaragua stayed at home and had little contact with each other, according to Senghas. The government expanded opportunities for special education with a new elementary school in Managua in 1977 and a vocational school in 1981.
Approximately 50 deaf students enrolled the first year, and the number grew to over 200 by 1981. No one taught the children to sign, but as soon as they were together they began to develop a system of gestures for communicating with each other, both in and out of school. Today there are approximately 800 deaf signers of NSL, ranging from four to 45 years old.
Each wave of children that enters the community develops NSL further, making it more complex and versatile, and signing with greater speed and fluidity.
"It's an unusual community, sort of upside-down, in the sense that the children lead the way. The children are the most fluent users of the language, not the older adults," Senghas said.
The researchers studied a trait central to all developed languages called "discreteness," meaning that information is packaged into separate elements that can be put together according to various rules. For example, no matter what the language, it consists of words, which combine to make sentences.