A sign language (also 'signed language') is a language which uses manual communication instead of sound to convey meaning - simultaneously combining handshapes, orientation and movement of the hands, arms or body, and facial expressions to fluidly express a speaker's thoughts. Sign languages develop in deaf communities, which can include interpreters and friends and families of deaf people as well as people who are deaf or hearing-impaired themselves.
When people using different signed languages meet communication is significantly easier than when people of different spoken languages meet. Sign Language in this respect gives access to an international deaf community.
However, contrary to popular belief, sign language is not universal. Wherever communities of deaf people exist, sign languages develop, but as with spoken languages, these vary from region to region. They are not based on the spoken language in the country of origin; in fact their complex spatial grammars are markedly different. However, various signed "modes" of spoken languages have been developed, such as Signed English and Walpiri Sign Language. Hundreds of sign languages are in use around the world and are at the core of local Deaf cultures.
Use of Signs in Hearing Communities
Gesture is a typical component of spoken languages. More elaborate systems of manual communication have developed in situations where speech is not practical or permitted, such as cloistered religious communities, scuba diving, television recording studios, loud workplaces, while hunting (see Kalahari bushmen) or in the game Charades.
On occasion, where the prevalence of deaf people is high enough, a deaf sign language has been taken up by an entire local community. Famous examples of this include Martha's Vineyard Sign Language in the USA, Kata Kolok in a village in Bali, Adamorobe Sign Language in Ghana and Yucatec Maya sign language in Mexico. It is interesting to note that deaf people in such communities are not socially disadvantaged.
A sign language or 'pidgin' arose among tribes of American Indians in the Great Plains region of North America (see Plains Indians). It was used to communicate among tribes with different spoken languages. There are a few users still alive today. Unlike other sign languages developed by hearing people, it shares the spatial grammar of deaf sign languages.
Linguistics of sign
In linguistic terms, sign languages can be as rich and complex as any spoken language, despite the common misconception that they are not "real languages". Professional linguists have studied many sign languages and found them to have every linguistic component required to be classed as a true language.
Sign languages are not simple pantomime, and they are not a visual rendition of a simplified version of any spoken language. They have rich, complex grammars and, like every other language used by people, they can be used to discuss any topic, from the simple and concrete to the lofty and abstract.
Sign languages, like spoken languages, organize elementary, meaningless units (phonemes in spoken languages, sometimes called cheremes in sign languages) into meaningful semantic units. The elements of a sign are Handshape (or Handform), Orientation (or Palm Orientation), Location (or Place of Articulation), Movement, and Non-manual markers (or Facial Expression) - summarised in the acronym HOLME.
Common linguistic features of deaf sign languages are extensive use of classifiers, a high degree of inflection, and a topic-comment syntax. Many unique linguistic features emerge from sign languages' ability to produce meaning simultaneously.
Sign Languages' relationships with spoken languages
A misconception sometimes held is that sign languages are dependent in some way on spoken languages, e.g. that they are merely the spelling out of the words of a spoken language using gestural symbols, or that they were invented by hearing people (many hearing teachers of deaf people's schools, for example Thomas Hopkins Gallaudet, are often incorrectly referred to as "inventors" of sign language).
Fingerspelling is used in sign languages, mostly for proper names, although it is merely one tool among many. In the past, the use of fingerspelling in sign languages was taken as one of the evidences that sign languages are just broken or simplified versions of spoken languages. To say that a signed language is not a true language because it uses fingerspelling is akin to saying that English is not a true language because it contains onomatopoeic words. Fingerspelling can sometimes be a source of new signs. Signs which have evolved from fingerspelling are called lexicalized signs.
On the whole, sign languages are independent of spoken languages and they follow their own developmental paths.
For example, British Sign Language and American Sign Language are different and mutually unintelligible (other than iconic signs), even though the hearing people of Britain and America share the same spoken language.
In addition, countries which have a single spoken language used throughout may have two or more signed languages being used within.
Conversely, an area that contains more than one native spoken language might use the same signed language, such as the case in Canada, the United States, and Mexico; all three use American Sign Language while there are native English, French and Spanish speakers within their borders.
Spatial grammar and Simultaneity
Further proof of the separation of sign languages from spoken ones is the fact that sign languages exploit the unique features of the visual medium.
Spoken language is aural and therefore linear. Only one sound can be made or received at a time whereas sign language is visual, hence, a whole scene can be taken in at once. Therefore, information can be loaded into many 'channels' and expressed simultaneously. As an illustration, in English, one could make the sentence, "I drove here." To add information about the drive though, one would have to make a longer sentence or even add an additional sentence. Such as, "I drove here and it was very pleasant." Or, "I drove here. It was a nice drive." However in American Sign Language, information about the pleasing nature of the drive can be conveyed simultaneously with the verb (drive) by taking advantage of the abilities of the visual mode of transmission which can take in non-manual signals (done with body posture and facial expression) at the same time as the manual sign signifying the verb, drive, is being seen and understood. Therefore, whereas in English the sentence "I drove here and it was very pleasant" is longer than the sentence, "I drove here", in American Sign Language both sentences are the same length.
Written forms of Sign Languages
One other way sign language differs from spoken is its ability to be written.
It would be a mistake however, to assume that sign languages are the only languages that have no written version.
Sign languages are not often written; most deaf people who use sign language read and write the spoken language of their country.
However, there have been attempts at developing systems for recording sign language.
Most of these have been academic attempts at transcription, which often suffer from being unable to capture all the physical features (especially the non-manual and positional ones) used by sign language. As a result, they have not been used outside research.
The only sign language writing system which has been actually used by deaf people to write, is SignWriting, which rather than being developed by a linguist was devised by a dancer.
Geographic distribution of Sign languages
In principle, one could state that each spoken language has a sign language counterpart inasmuch as each linguistic population will contain deaf members who will generate a sign language.
Variations within a 'national' sign language can usually be correlated to the geographic location of (residential) schools for the deaf.
An "international sign language" Gestuno is used for international Deaf events such as the Deaflympics, but its use is very limited, and could be likened to that of Esperanto.
Certain sign languages are developed within a family. For instance, when hearing parents who have no knowledge of or training in a signed language have a deaf child, an informal system of signs will naturally develop, unless repressed by the parents, by which they can communicate. The term for these mini-languages is kitchen sign or home sign. Home Sign is a deaf child's attempt to create a language within the span of a single lifetime due to the absence of any other way to communicate. Although this type of communcation sytem does not meet the standards linguists set to describe a complete language, it is an extreme yet familiar occurrence among deaf children in hearing families that use no form of signing whatsoever.
Contemporary local sign languages
Purpose-specific sign languages
Archaic Sign Languages
There are also a large number of less formally organised but still widely understood gesticulations and mimes.
These range from expressing universal needs such as pointing to the mouth or rubbing the stomach to indicate a desire for food, to more insulting gestures such as the one-finger salute. It should be noted that not only do these not form a coherent language but their meaning may vary between cultures.
- Kendon, Adam. 1988. Sign Languages of Aboriginal Australia: Cultural, Semiotic and Communicative Perspectives. Cambridge: Cambridge University Press.
- Branson, J., D. Miller, & I G. Marsaja. 1996. "Everyone here speaks sign language, too: a deaf village in Bali, Indonesia." In: C. Lucas (ed.): Multicultural aspects of sociolinguistics in deaf communities. Washington, Gallaudet University Press, pp. 39-5