“What we didn’t know until very recently is that Hawaiʻi is home to a second, highly endangered, language that is found nowhere else in the world,” said William O’Grady, a linguistics professor at the University of Hawaiʻi at Mānoa. … “Our information on Hawaii Sign Language goes back to 1800s, long before the influence of American Sign Language,” said Barbara Earth, an adjunct assistant professor at the Mānoa Department of Linguistics and one of the research team leaders.
Linda Lambrecht, an American Sign Language instructor at Kapiʻolani Community College, who was also a research team leader, inspired the study. HSL was the first language Lambrecht learned and she spoke it as child before ASL became the dominant sign language in the 1940s and 1950s. … This is the first time since the 1930s, that a previously unknown language, either spoken or signed, has been documented in the United States.
That page links to a press release with more information; anybody know what language was discovered in the ’30s?