American Sign Language (ASL) is a natural language that serves as the predominant sign language of deaf communities in the United States and most of Anglophone Canada. ASL is a complete and organized visual language that is expressed by employing both manual and nonmanual features. Besides North America, dialects of ASL and ASL-based creoles are used in many countries around the world, including much of West Africa and parts of Southeast Asia. ASL is also widely learned as a second language, serving as a lingua franca. ASL is most closely related to French Sign Language (LSF). It has been proposed that ASL is a creole language of LSF, although ASL shows features atypical of creole languages, such as agglutinative morphology.
ASL is not based on English; it has its own grammar and vocabulary. ASL is not a universal language; there are between 200 and 300 officially recognized signed languages around the world, and ASL is one of those languages.
ASL originated in the early 19th century in the American School for the Deaf in Hartford, Connecticut, from a situation of language contact. Since then, ASL use has been propagated widely by schools for the deaf and deaf community organizations. Despite its wide use, no accurate count of ASL users has been taken. Reliable estimates for American ASL users range from 250,000 to 500,000 persons, including a number of children of deaf adults (CODA) and other hearing individuals.
Signs in ASL have a number of phonemic components, such as movement of the face, the torso, shoulders, and the hands. ASL is not a form of pantomime, although iconicity plays a larger role in ASL than in spoken languages. English loan words are often borrowed through fingerspelling, although ASL grammar is unrelated to that of English. ASL has verbal agreement and aspectual marking and has a productive system of forming agglutinative classifiers. Many linguists believe ASL to be a subject–verb–object language. However, there are several other proposals to account for ASL word order.
ASL emerged as a language at the American School for the Deaf, co-founded by Thomas Gallaudet and Laurent Clerc in 1817, which brought together Old French Sign Language, several indigenous sign languages, Martha's Vineyard sign language, and various home sign systems. ASL was created in that situation by language contact. ASL is influenced by its forerunners, yet linguistically distinct.
The influence of French Sign Language (LSF) on ASL is readily apparent; for example, it has been found that about 58% of signs in modern ASL are cognates to Old French Sign Language signs. However, that is far less than the standard 80% measure used to determine whether related languages are actually dialects. That suggests nascent ASL was highly affected by the other signing systems brought by the ASD students although the school's original director, Laurent Clerc, taught in LSF. In fact, Clerc reported that he often learned the students' signs rather than conveying LSF:
I see, however, and I say it with regret, that any efforts that we have made or may still be making, to do better than, we have inadvertently fallen somewhat back of Abbé de l'Épée. Some of us have learned and still learn signs from uneducated pupils, instead of learning them from well instructed and experienced teachers.
It has been proposed that ASL is a creole in which LSF is the superstrate language and the native indigenous sign languages are substrate languages. However, more recent research has shown that modern ASL does not share many of the structural features that characterize creole languages. ASL may have begun as a creole and then undergone structural change over time, but it is also possible that it was never a creole-type language to begin with. There are modality-specific reasons that signed languages tend towards agglutination, such as the ability to simultaneously convey information via the face, head, torso, and other body parts. That might override creole characteristics such as the tendency towards isolating morphology. Additionally, Laurent Clerc and Thomas Hopkins Gallaudet may have used an artificially constructed form of manually coded language in instruction rather than true LSF.
Although the United States, the United Kingdom, and Australia share English as a common oral and written language, ASL is not mutually intelligible with either British Sign Language (BSL) or Auslan. All three languages show degrees of borrowing from English, but that alone is not sufficient for cross-language comprehension. However, that does not seem justified historically for ASL and Auslan, and it is likely that the resemblance is caused by the higher degree of iconicity in sign languages in general as well as contact with English.
American Sign Language is growing in popularity in many states. Many high school and university students desire to take it as a foreign language. This increased interest is also reflected beyond education, with ASL appearing more frequently in mainstream media through adaptations in film and popular media. ASL has also gained greater public visibility through social media and online platforms, where deaf and hard-of-hearing users share educational content and resources for learning the language. Research on video-sharing platforms such as TikTok has found that there are opportunities for ASL users to create and distribute sign language content to wider audiences.
ASL users, however, have a very distinct culture. Their facial expressions and hand movements reflect what they are communicating. They also have their own sentence structure, which sets the language apart from other spoken and signed languages. ASL allows information to be expressed spatially, with meaning that is conveyed through the placement and movement of signs in relation to one another rather than through a strictly linear sequence.
American Sign Language is now being accepted by many colleges as a language eligible for foreign language course credit; many states are making it mandatory to accept it as such. In some states however, this is only true with regard to high school coursework. Organizations such as the American Sign Language Teachers Association support ASL education by providing professional development, certification and networking opportunities for teachers of ASL and Deaf Studies.
Prior to the birth of ASL, sign language had been used by various communities in the United States. In the United States, as elsewhere in the world, hearing families with deaf children have historically employed ad hoc home sign, which often reaches much higher levels of sophistication than gestures used by hearing people in spoken conversation. As early as 1541 at first contact by Francisco Vásquez de Coronado, there were reports that the Indigenous peoples of the Great Plains widely spoke a sign language to communicate across vast national and linguistic lines.
In the 19th century, a "triangle" of indigenous sign languages developed in New England: one in Martha's Vineyard, Massachusetts; one in Henniker, New Hampshire, and one in Sandy River Valley, Maine. Martha's Vineyard Sign Language (MVSL), which was particularly important for the history of ASL, was used mainly in Chilmark, Massachusetts. Due to intermarriage in the original community of English settlers of the 1690s, and the recessive nature of genetic deafness, Chilmark had a high 4% rate of genetic deafness. MVSL was used even by hearing residents whenever a deaf person was present, and also in some situations where spoken language would be ineffective or inappropriate, such as during church sermons or between boats at sea.
ASL is thought to have originated in the American School for the Deaf, founded in Hartford, Connecticut, in 1817. Originally known as The American Asylum, At Hartford, For The Education And Instruction Of The Deaf And Dumb, the school was founded by the Yale graduate and divinity student Thomas Hopkins Gallaudet. Gallaudet, inspired by his success in demonstrating the learning abilities of a young deaf girl Alice Cogswell, traveled to Europe in order to learn deaf pedagogy from European institutions. Ultimately, Gallaudet chose to adopt the methods of the French Institut National de Jeunes Sourds de Paris, and convinced Laurent Clerc, an assistant to the school's founder Charles-Michel de l'Épée, to accompany him back to the United States. Upon his return, Gallaudet and Clerc founded the ASD on April 15, 1817. In 2019, April 15 was declared as the National American Sign Language Day.