Another way to mark agreement in LIS is through non-manual markers. Non-manual agreement in LIS is optional and may be realized with all verb classes.
The two non-manual articulators involved are head tilt (ht) and eye gaze (eg). Commonly, the head tilts toward the location of the subject argument and eye gaze is directed towards the location of the object argument simultaneously to the production of the verbal sign. The two non-manual markers may be produced singularly, as in (a), or together, as in (b). With intransitive predicates, either one of the two non-manual articulators can mark subject agreement (c).
ht: a
a. l-u-c-aa p-a-o-l-ob ahateb
‘Luca hates Paolo.’
ht: a
eg: b
b. l-u-c-aa p-a-o-l-ob ahateb
‘Luca hates Paolo.’
eg
c. book CL: ‘fall_down’
‘The book falls down.’