There are numerous popular misconceptions about sign languages. One of these misconceptions has it that sign languages are “languages on the hands,” that is, that sign language lexemes as well as morphologically and syntactically complex structures are articulated entirely by the hands (and possibly the lower arm).
In the course of this chapter, we will show that this statement is far from appropriate. Surely, the hands play an important role in the articulation of signed utterances, but other articulators – the body, the head and (parts of) the face – are just as important. All linguistically significant elements that are not expressed by the hands are referred to as “nonmanual markers” or just “nonmanuals.” Actually, it has been shown that signers, while communicating, do not focus their attention on each other's hands but rather on the face, where essential grammatical information is encoded nonmanually (Siple 1978, Swisher, Christie & Miller 1989).
Linguistically significant nonmanuals have to be distinguished from purely affective nonmanual markers such as facial expressions or head movements expressing disgust, disbelief or surprise, which are used by signers just as they are used by speakers. Differentiating between the two types of markers is not always straightforward, but certain distinguishing criteria have been suggested. The scope and the timing of linguistic nonmanual behaviors, for instance, is linguistically constrained relative to the manual sign(s) they accompany in a way that affective markers are not (e.g., Baker-Shenk 1983, Reilly & Anderson 2002).