Mouth gestures are actions of the mouth that are not derived from spoken Italian. Although LIS signers use less mouth gestures than mouthings, the former appear more uniform than the latter.
The category of mouth patterns is not strictly associated with the mouth. In a broader sense, it involves different components: jaw aperture, position of the cheeks, tongue and lips, and use of air. To give an idea of the variety of mouth gestures attested in LIS, some examples are listed and shown below. Note that position of the lips and use of air often co-occur. Mouth gestures can involve: i) jaw aperture (e.g. lowered jaw and open mouth ‘om’ in the sign astonishment), ii) position of the cheeks (e.g. puffed cheeks ‘pc’ in the sign fat), iii) position of the tongue (e.g. tongue protrusion ‘tp’ and/or contracted cheeks in the sign thin), iv) position of the lips (e.g. compression of the lower lip performed by the upper teeth ‘tl’ in the sign be_sorry), and v) use of air (e.g. occlusion followed by a sudden release of air in the sign transgress).
lowered jaw+om
a. astonishment
pc
b. fat
tp
c. thin
tl
d. be_sorry
blow
e. transgress
The relationship between mouth gesture and manual sign can reflect different degrees of iconicity. It can be transparent, translucent, or opaque. In a transparent relationship, the mouth gesture iconically reflects the meaning of the sign. For example, in the articulation of the sign ice_cream_eat, the tip of the tongue is protruded (tp) as in the action of licking. A translucent relationship is clear to non-signers once it is explicitly explained. For example, in the articulation of the sign like.not, the tip of the tongue is visibly protruded (tp), as similarly happens when people belonging to the Italian culture don't like something and stick out their tongue. In an opaque relationship, the link between mouth gesture and manual sign is purely conventional. For example, the sign impossible_pa_pa and the associated mouth gesture [pa pa] are not semantically related.
tp
a. ice_cream_eat
tp
b. like.not
[pa pa]
c. impossible_pa_pa
In some cases, the articulatory features of the mouth gesture are associated to the meaning through a metaphorical relation. For instance, protrusion of the tongue frequently suggests negative connotation, occlusives suggest immediacy, and lengthening of the mouth gesture indicates temporal continuity.
Mouth gestures not only contribute to the formation of signs, but they can also be used to convey specific adverbial meanings (LEXICON 3.5).