ASL has been used by Deaf people in the United States since the early 1800's. The language has evolved into a rich, complex language that uses the hands, facial expressions, head and body movements, and 3-D space.The five parameters are:
Handshape; this refers to the hand configuration which is used in beginning any word production in American Sign Language (ASL). If you're familiar with ASL Alphabet, you'll notice that every word begins with one of at least forty handshapes found in the manual alphabet. Here are just a three examples of handshapes: the 'c' as in class; the open 'a' as in ahead: the bent 'v' as in squirrel.
Palm orientation; this refers to the direction in which the hand is turned to produce a sign. Palm orientation is the direction of your palm which may include palm up, palm down, palm right, palm left, palm outward (away from you) or palm inward (palm facing you).
Movement; this refers to the changing of the location of the hands within the set physical parameters during sign production. For example, a sign may be moving away from you or towards you to indicate a directional verb such as 'I give you the book" or "She gives him a pencil". Movement also refers to the frequency of an action.
Location; this refers to the physical parameters or bodily location where the sign are produced. The general physical parameters for sign language production are approximately four inches above the head, elbow room as with hands on waist, and about four inches below the belly button or belt buckle.