Sign Language (known as BSL) is the natural language of the British deaf community, part of the same language family as Australian Sign Language (Auslan) and New Zealand Sign Language (NZSL). BSL also has more distant connections—for example, to some varieties of South African Sign Language, Maltese Sign Language, and Maritime Sign Language (in Canada). It is not, however, mutually intelligible with sign languages used in other English-speaking countries, such as Irish Sign Language (ISL) or American Sign Language (ASL). This entry describes the prevalence and history of BSL; its sign categories, including fingerspelling; and its morphology, syntax, and sociolinguistic variation. The entry ends with a brief section on research.