Sign language is a language that uses manual signs to convey meaning by a combination of body parts and facial expressions into shapes, orientation and movements.
Human beings’ astounding capacity to imitate a wide range of behaviors observed through body postures and facial expressions becomes the basis of sign language.
A wide variety of sign languages are currently in use: American Sign Language used by the deaf to communicate is different from the British sign language that uses finger alphabet.
The researchers at Oklahoma University have successfully tried to teach the rudimentary sign language to chimpanzees.
The deaf people have been known to communicate by using sign language from ancient times as seen from their references in ancient Greek literature.
Juan Pablo Bonet, a Spaniard, first published a modern treatise in 1620 on sign language phonetics detailing its alphabet of manual gestures.
Sign languages do not linguistically correlate to spoken languages but rather to the geographical location or nation where it is taught to the deaf.
The signs are often arbitrary, conventional and usually do not have a visual correlation to the underlying object or action just as spoken languages are not always onomatopoeic (representing related sounds).
Unlike spoken language, which involves transmission of linear stream of sounds, the sign language exploits the visual perception for the simultaneous processing of a variety of hues of information.
In the absence of any support or feedback from the community, a deaf child naturally invents a primitive sign language to meet its communication needs.