Indonesian Sign Language (Indonesian: Bahasa Isyarat Indonesia, BISINDO) is any of several related deaf sign languages of Indonesia, at least on the island of Java. It is based on American Sign Language, with local admixture in different cities. Although presented as a coherent language when advocating for recognition by the Indonesian government and use in education, the varieties used in different cities may not be mutually intelligible.
Specifically, the only study to have investigated this, Isma (2012),[2] found that the sign languages of Jakarta and Yogyakarta are related but distinct languages, that they remain 65% lexically cognate but are grammatically distinct and apparently diverging. They are different enough that Isma's consultants in Hong Kong resorted to Hong Kong Sign Language to communicate with each other. Word order in Yogyakarta tends to be verb-final (SOV), whereas in Jakarta it tends to be verb-medial (SVO) when either noun phrase could be subject or object, and free otherwise. The varieties in other cities were not investigated.
^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. Conversely, ASL and BSL both originated in English-speaking countries but are not related to each other; ASL however is related to French Sign Language.
^b Denotes the number (if known) of languages within the family. No further information is given on these languages.