American Sign Language (ASL), which is the first language of many deaf people in North America, uses hand gestures, facial expressions, and other body movements to communicate. ASL is one of the four most commonly used languages in the United States.
ASL was first introduced to American in 1817. In that year, a French teacher who came to America to teach brought with him the French sign Language (FSL) and taught it to his deaf students. The students then added their own American signing and changed the FSL into the ASL. Modern ASL and FSL share some elements, including a large amount of vocabulary. However, an ASL user cannot understand an FSL user.
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.