Original Bangkok Sign Language (7187) = Critically Endangered (100 percent certain, based on the evidence available) (OBSL is currently only used in very limited social situations. Instead MTSL replaces OBSL in almost all interaction. Because of this situation, OBSL is a highly endangered sign language. It is quite likely that if documentation of OBSL is not completed in one generation that OBSL will be lost to linguistic study forever, since there is currently no extensive record of OBSL.) (see Woodward et al. 2015)
Glottolog
Original Bangkok Sign Language at Endangered Languages Project
Wikipedia
Wikidata