Sign language

A natural language that uses manual articulation (handshapes, movement, location relative to the body), facial expressions, and body posture to convey meaning, serving as the primary or preferred language of many deaf and hard-of-hearing people. Sign languages are fully developed linguistic systems with their own grammar, syntax, and morphology — they are not visual representations of spoken languages. Each country or region typically has its own sign language (e.g., American Sign Language, British Sign Language, Nederlandse Gebarentaal), and these are mutually unintelligible. In accessibility, sign language recognition is important at multiple levels: providing sign language interpretation for live events and media content, designing interfaces that accommodate sign language communication (such as adequate video quality for sign visibility), and recognising that for many Deaf people, written text is a second language, meaning that text-only accessibility measures may be insufficient.