Signing space is a three-dimensional space from about the mid-torso to just above the head, extending forward from the chest to about one-arm length away, and extending about half an arm's length on both sides. During most signs, the hands and arms do not go beyond this space.
Fingerspelling space is a small space just large enough to fit the hand; it is located midway near the chin and shoulder. Note that the fingerspelling space is still located within the signing space. Fingerspelling space is where the hands are used to spell out letters borrowed from a written language.
One or both hands may be used in signing, depending on the sign and the sign language. In the case where two-hands are used where only one hand is moving, the moving hand is called the dominant hand (DH) and the stationary hand is called the non-dominant hand (NDH) or the passive hand. Two-handed signs where both hands move in the same path and use the same handshapes are sometimes called symmetrical signs.
There are no left-handed or right-handed signs, one-handed signs may be performed with either left hand or right hand; and either hand may be used as the dominant hand in two-handed signs. In practice, right-handed people usually use their right hand for one-handed signs, fingerspelling, and as the DH in two-handed signs; and left-handed people usually use their left.