Hawaiʻi Sign Language (HSL), also known as Old Hawaiʻi Sign Language or Hawaiʻi Pidgin Sign Language, is an indigenous sign language used in Hawaiʻi. Although historical records document its presence on the islands since the 1820s, it was not described by linguists until 2013. Now largely supplanted by American Sign Language (ASL), it is almost extinct and is used only by a few elderly people, who are bilingual in ASL. Although previously believed to be related to ASL, the two languages are in fact unrelated.
The term pidgin in some names used for HSL is due to its association with the spoken language Hawaiʻi Pidgin. HSL is not itself a pidgin, nor even related to Hawaiʻi Pidgin. For this reason, linguists who have begun to document the language prefer the name Hawaiʻi Sign Language, and that is the name used for it in ISO 639-3 as of 2014.
Village sign use, by both deaf and hearing, is attested from 1820. There's the possibility of influence from immigrant sign later that century, though HSL has little in common today with ASL or other languages. The establishment of a school for the deaf in 1914 strengthened the use of sign among the students. However, the introduction of ASL in 1941 in place of purely oral instruction resulted in a shift to that language.
^a Sign-language names reflect the region of origin. Natural sign languages are not related to the spoken language used in the same region. For example, French Sign Language originated in France, but is not related to French.