Researchers have for the first time documented Hawaiian Sign Language (HSL).
There is written evidence dating back to the 1800s showing the language existed but it is now spoken by only around 40 islanders. In the 1940s it began to be phased out in favour of American Sign Language (ASL).
Work to preserve the language is urgent as many of the speakers are now over 80. Researchers are working on a long term study, which aims to produce a dictionary and videotaped data. They also hope to revitalise the language, which is distinct from ASL but shares some signs.
Take a look at the video below to see a demonstration of HSL and how it compares to ASL.