1. A means of COMMUNICATION using gestures, usually between speakers of different languages: Plains Indian sign language.
2. Also sign. A system of manual communication used by the deaf. The signs are conventional movements that represent a range of meanings similar to those expressed by speech (including abstract notions), and differing widely between communities. There are two main types: concept-based systems used as natural languages; language-based systems often used when teaching deaf children to communicate. There are rules governing the way signs are formed and there are many thousands of signs in the leading sign languages.
When a sign language becomes widely used, it develops varieties similar to those in spoken language. Several ‘mixed’ varieties exist, where people use signs that show the influence of the speech of the community to which the signer belongs. Not only is it impossible for French and English signers to understand each other (without one person learning the other's sign), but there is little mutual comprehension between signers of American Sign Language (short forms Ameslan, ASL) and British Sign Language (short from BSL), because the sign vocabulary is different. However, both sign languages can be traced to the early 19c work of two educators of the deaf, Thomas Gallaudet in the US and Laurent Clerc in France. The signs express a range of meanings and nuances comparable to those expressed by spoken or written language. For example, time relationships can be expressed by dividing the space in front of the body into zones, such as further forward for future time and further back for past time. Personal pronouns can be distinguished using different spatial areas: you is front-centre and various third-person forms are signed to the right and left. Use is made of repeated signs to convey such notions as plurality, degree, or emphasis. These signs are used simultaneously with other movements, such as facial expressions, eye movements, and shifts of the body: for example, questions can be signalled by a facial expression, such as raised eyebrows and a backwards head tilt. Fluent signing (between one and two signs per second) produces a conversational rate comparable to that of speech.
Sign languages within the community of English have been devised at various times to bring the signer into a close relationship with spoken or written English. These include: (1) Finger spelling (dating at least from the 19c), in which each letter of the alphabet has its own sign, using two hands in the British version and one hand in the American version. (2) Cued Speech (1966), a system of hand cues used alongside lip movements to draw attention to the phonemic contrasts in speech. (3) More complex systems that aim to reflect features of English grammar, including Signed English or Sign English (1966), Seeing Essential English (1969), Manual English (1972).
Sign languages are the principal means of communication among members of deaf communities, with most countries having their own distinct sign language. In the United States, American Sign Language (ASL) is the language typically used by persons who have grown up deaf. Sign languages have gained considerable attention outside of deaf communities through the use of signs to foster communication in minimally verbal hearing persons (e.g., children with autism) and with nonhuman primates.
For centuries, sign languages were viewed as primarily pantomimic—not true languages at all. This belief helped support the oral approach to deaf education, a strategy that eschewed signing and focused on speech. Oralists advised parents of deaf children to shun all forms of manual communication and to promote spoken language acquisition through speech training, hearing amplification, speech reading, and writing. Sadly, many young people failed to attain sufficient speech mastery through this approach. As a result, many schools for deaf students today embrace a total communication approach. In this approach, all avenues of communication, including signing, are used to foster deaf students' language skills.
The pioneering research of William Stokoe (1919-2000) did much to alter the view that sign languages were not true languages. Stokoe identified three aspects of sign formation that distinguish one ASL sign from another: the place where the sign is made, the configuration and orientation of the hands, and the hand and arm movement forming the sign. These sign formational aspects function in a manner similar to that of phonemes in spoken languages. Subsequent studies demonstrated that ASL not only has an extensive lexicon but it also operates as a rule-governed, grammatical system. Most linguists now recognize ASL and other sign languages used in deaf communities as full and genuine languages.
Klima, Edward S., and Ursula Bellugi. The Signs of Language. Cambridge, MA: Harvard University Press, 1979.
Wilbur, Ronnie B. American Sign Language: Linguistic and Applied Dimensions, 2nd edition. Boston: College-Hill Press, 1987.
sign lan·guage • n. a system of communication using visual gestures and signs, as used by deaf people.