Language is so essential to the human beings that, in spite of the existing communication problems, they look for a way to satisfy this faculty. This is what happens to deaf people, that communicate through sign languages. .
The languages in the world can be expressed in different ways. For example, Portuguese, English ans Spanish are spoken languages, whose comunication is oral. By contrast, American Sign Language, Brazilian Sign Language and Spanish Sign Language are sign languages, which use a manual way of communication. Independently of the way they communicate, languages express the language faculty (Chomsky, 1995, apud Quadros, 2003). .
Sign languages' structure can be considered as complex as spoken and written languages' structure, and also perform a similar range of funtions, as Stokoe (1965, apud Quadros, op. cit.) defends. .
No single sign language exists. There are many such languages (American, French ) and they are not mutually intelligible. They use different signs and different rules of sign formation and sentence structure. .
LIBRAS (Brazilian Sign Language) is the sign language used by deaf people that live in the urban centers of Brazil, where there are deaf communities. Besides this one, there is another kind of sign language, used by the Urubus-Kaapor indians in the Amazon Forest. But this work is investigating just the first one, that is different and independent from Portuguese - the Brazilian spoken language. The differences are not only on the way their communication takes place, but also on the grammatical structures. .
The history of deaf communities around the world is strongly associated to their educational programmes. The three most important programmes are Oralism, Total Communication and Bilingualism. The first one defends the exclusive teaching of speech. The second one is a combines approach, in which speech, some kind of signing system, unsystematic gestures, lips reading etc.
