Sign Language

Sign languages are natural human languages expressed through the visual-gestural modality rather than the vocal-auditory channel. Each sign language is independent and has its own grammar, phonology (or cherology), and lexicon; signed languages are not universal and are not derived from spoken languages. There are hundreds of distinct sign languages worldwide, including American Sign Language (ASL), British Sign Language (BSL), Australian Sign Language (Auslan), and many others. The ISO 15924 code Sign is used to tag content in sign languages when no more specific code is applicable. Various writing systems for sign languages exist, including SignWriting (a featural script that represents handshapes, movement, and facial expression) and the Hamburg Notation System (HamNoSys), though none has achieved widespread standardised use. Digital and multimedia formats are increasingly used to record and transmit signed content.