The shaka sign - a person's thumb and pinkie extended, the rest of the fingers in a fist - is uniquely Hawaiian, a way to say "right on," "hang loose" or simply hello.

But it turns out it's not the only way islanders have used their hands to communicate.

A research group at the University of Hawaii at Manoa announced Friday that they had documented - for the first time - Hawaii Sign Language, or HSL, which deaf people across the islands' diverse ethnic groups have used for decades if not longer.

While there is written evidence dating back to 1821 indicating such a language existed, beginning in the 1940s it started to get largely phased out in favor of American Sign Language.