American Sign Language (ASL) is a complete, complex form of manual communication in which hand movements are combined with facial expressions and body language to form a visual-spatial language without sound. ASL is not related to spoken English and is considered linguistically as a complete and full language in its own right. British Sign Language (BSL) is also a complete, distinguishable language.
Although the United States and Great Britain share English as a common Language, American Sign Language and British Sign Language are not mutually intelligible. These differences are due to the separate historical development paths of the two languages. One readily apparent difference is that ASL uses a one-handed alphabetical system, while BSL uses a two-handed alphabet.
Linguistics is the science of language, including phonetics, phonology,morphology, syntax, semantics, pragmatics, and historical linguistics. As distinct languages, ASL and BSL include all of these linguistic elements.