Sign languages can evolve from scratch in the space of a generation.© Punchstock

New languages can develop consistent rules of grammar within a single generation of their birth, a study of an Israeli sign language has shown.

The Al-Sayyid Bedouins, who live in Israel's Negev region, 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.

Sentences in Al-Sayyid Bedouin sign language have a word order of 'subject, object, verb' (SOV), as in the phrase 'I apple give'. Israel's spoken languages, Arabic and Hebrew, use 'subject, verb, object' (SVO). The same goes for English, as in 'I give apple'.

"We didn't expect to see word order so quickly, and didn't expect to see this particular word order," says Carol Padden of the University of California, San Diego, who led the study. The discovery suggests that grammar appears early in the development of face-to-face languages. Written language can take centuries to develop consistent grammar.

Impressive progress

Speedy development in sign language has been seen before. Nicaraguan deaf people have adopted a common sign language over the past 25 years, since they were brought together in a specialist school system for the deaf. But the Al-Sayyid Bedouins are the first group to be studied that has developed a sign language with no outside influence.

The language's rapid progress is impressive, agrees Steven Pinker, a linguist at Harvard University in Cambridge, Massachusetts. "This finding suggests that the human mind has the motive and means to create an expressive, grammatical language without requiring many generations of fine-tuning," he says.

But there is nothing remarkable about the contrast between the signers' SOV structure and the SVO grammar of Israel's spoken languages, he says. Languages are split between the two and some switch from one to the other, as shown by archaic English phrases that use SOV, such as "With this ring, I thee wed."

The simple structure of Al-Sayyid Bedouin sign language is an important convention that will allow later sophistication, say Padden and her colleagues, writing in the Proceedings of the National Academy of Sciences¹. The Al-Sayyid Bedouins can sign 'James Jan kiss' and know that James has kissed Jan, rather than the other way around. Once a language is unambiguous outside its immediate context, complicated rules about agreements between subjects and verbs are able to evolve.

But it will take many generations, says Pinker, for such further subtleties to emerge. 

University of California, San Diego

Harvard University

• References

  1. Sandler W., Meir I., Padden C. & Aronoff M., Proc. Natl Acad. Sci. USA, published online, doi:10.1073/pnas.0405448102 (2005).