Mouth gestures in LSC may be of different types: they can be i) imitative, ii) compulsory, or iii) they can display information about nouns, verbs, adjectives, or adverbs. Imitative mouth gestures copy the action of the mouth when carrying out. For instance, in the sign kiss the lips adopt the form of an actual kiss. The same happens with the signs bite and ruminate, which imitative the corresponding actions.
a) kiss
b) bite
c) ruminate
Compulsory mouth gestures may be defined as mouth gestures that are obligatory in the articulation of a specific lexical sign. The sign there_be in LSC needs to be articulated with a repeated movement of the tongue, as shown in the video below; and the same happens in the signs there_be_not and appropriate, which have an inherent mouth gesture that cannot be removed without affecting the phonology of the sign.
a) there_be
b) there_be_not
c) appropriate
Lastly, LSC has mouth gestures that provide information about nouns, verbs, adjectives or adverbs. The signs below are some examples of adjectives and adverbs that inherently have a specific mouth gesture. These signs can be expressed only with the mouth gesture in combination with a noun or a verb.
a) big
b) small
c) thin
d) fast
e) quite