Nonmanual
Nonmanual, in the context of sign languages, refers to the set of facial, head, eye, and upper-body movements that accompany manual signs. Nonmanual signals include facial expressions (eyebrows, eyes, cheeks, mouth), head and shoulder movements, gaze direction, and torso orientation. They function together with hand signs as an integrated grammatical system; nonmanuals are not separate words but part of the sign's meaning and syntactic function.
Nonmanuals convey grammatical information such as negation, question type, aspect, and topic marking, as well as
Nonmanuals are language-specific in their exact form and use, but they are a common feature of many
Researchers study nonmanuals using video analysis and transcription schemes to capture the timing, simultaneity, and interaction