American Sign Language (ASL) is a beautiful language and culture that is expressed through visual gestures and signs. The National Association of the Deaf (NAD) explains certain aspects of sign language.
"The shape, placement, and movement of the hands, as well as facial expressions and body movements, all play important parts in conveying information.
Sign language is not a universal language -- each country has its own sign language, and regions have dialects, much like the many languages spoken all over the world. Like any spoken language, ASL is a language with its own unique rules of grammar and syntax. Like all languages, ASL is a living language that grows and changes over time.
ASL is used predominantly in the United States and in many parts of Canada. ASL is accepted by many high schools, colleges, and universities in fulfillment of modern and “foreign” language academic degree requirements across the United States."