Diseases

In spoken language, the different sounds created by words and tones of voice (intonation) are the most important devices used to communicate. Sign language is based on the idea that sight is the most useful tool a deaf person has to communicate and receive information. Thus, ASL uses hand shape, position, and movement; body movements; gestures; facial expressions; and other visual cues to form its words. Like any other language, fluency in ASL happens only after a long period of study and practice. Even though ASL is used in America, it is a language completely separate from English. It contains all the fundamental features a language needs to function on its own--it has its own rules for grammar, punctuation, and sentence order. ASL evolves as its users do, and it also allows for regional usage and jargon. Every language expresses its features differently; ASL is no exception. Whereas English speakers often signal a question by using a particular tone of voice, ASL users do so by raising the eyebrows and widening the eyes. Sometimes, ASL users may ask a question by tilting their bodies forward while signaling with their eyes and eyebrows. Just as with other languages, specific ways of expressing ideas in ASL vary as much as ASL users themselves do. ASL users may choose from synonyms to express common words. ASL also changes regionally, just as certain English words are spoken differently in different parts of the country. Ethnicity, age, and gender are a few more factors that affect ASL usage and contribute to its variety.

No one form of sign language is universal. For example, British Sign Language (BSL) differs notably from ASL. Different sign languages are used in different countries or regions.

Some studies focus on the age of ASL acquisition. Age is a critical issue for people who acquire ASL, whether it is a first or second language. For a person to become fully competent in any language, exposure must begin as early as possible, preferably before school age. Other studies compare the skills of native signers and non-native signers to determine differences in language processing ability. Native signers of ASL consistently display more accomplished sign language ability than non-native signers, again emphasizing the importance of early exposure and acquisition. Other studies focus on different ASL processing skills. Users of ASL have shown ability to process visual mental images differently than hearing users of English. Though English speakers possess the skills needed to process visual imagery, ASL users demonstrate faster processing ability--suggesting that sign language enhances certain processing functions of the human brain.

American Sign Language (ASL) is a complete, complex language that employs signs made with the hands and other movements, including facial expressions and postures of the body. It is the first language of many deaf North Americans, and one of several communication options available to deaf people. ASL is said to be the fourth most commonly used language in the United States.

The exact beginnings of ASL are not clear. Many people believe that ASL came mostly from French Sign Language (FSL). Others claim that the foundation for ASL existed before FSL was introduced in America in 1817. It was in that year that a French teacher named Laurent Clerc, brought to the United States by Thomas Gallaudet, founded the first school for the deaf in Hartford, Connecticut. Clerc began teaching FSL to Americans, though many of his students were already fluent in their own forms of local, natural sign language. Today's ASL likely contains some of this early American signing. Which language had more to do with the formation of modern ASL is difficult to prove. Modern ASL and FSL share some elements, including a substantial amount of vocabulary. However, they are not mutually comprehensible.

Parents are often the source of a child's early acquisition of language. A deaf child who is born to deaf parents who already use ASL will begin to acquire ASL as naturally as a hearing child picks up spoken language from hearing parents. However, language is acquired differently by a deaf child with hearing parents who have no prior experience with ASL. Some hearing parents choose to introduce sign language to their deaf children. Hearing parents who choose to learn sign language often learn it along with their child. Nine out of every ten children who are born deaf are born to parents who hear. Other communication models, based in spoken English, exist apart from ASL, including oral, auditory-verbal, and cued speech. As with any language, interaction with other children and adults is also a significant factor in acquisition.

Parents should introduce deaf children to language as early as possible. The earlier any child is exposed to and begins to acquire language, the better that child's communication skills will become. Research suggests that the first six months are the most crucial to a child's development of language skills. All newborns should be screened for deafness or hearing loss before they leave the hospital or within the first month of life. Very early discovery of a child's hearing loss or deafness provides parents with an opportunity to learn about communication options. Parents can then start their child's language learning process during this important stage of development.