In LSC, non-manuals also play a role in the encoding of referential status, with indefiniteness being expressed by a particular non-manual marker that involves the lower part of the face and consists of sucking in the cheeks and pulling the corners of the mouth down. This is sometimes combined with a shrug. This facial expression, which is shown below, is aligned with indefinite noun phrases that are not novel, non-unique, and not familiar.
Non-manual associated with indefiniteness
(recreated from Barberà, 2012: 238)