The fourth strategy for distinguishing syntactical subjects and objects in LIS is the analysis of null arguments (SYNTAX 2.1.2). Very commonly in LIS, subject and object can be omitted thanks to the context, which plays an important role in allowing arguments to be unexpressed. The example below shows one such case, where both subject and object can be omitted.
Context: A person known by the signer is mentioned in the discourse.
be_familiar
‘(I) know (her).’
In LIS, the subject is more easily omitted than object. Especially when subjects are also topics and are easily accessible to the interlocutor, they seem likely to be omitted. Moreover, the distribution of null arguments in LIS seem to correlate with many other linguistic factors, such as the presence of agreement verbs and verb classifiers. In the presence of these elements, arguments can easily be left unexpressed in LIS. This happens in the example below, where the use of the classifier V for the predicative classifiermeaning ‘(to) walk’ is automatically interpreted as referred to gianni, not to his dog. So, the name gianni does not need to be repeated.
rs: dog
gianni house arrive. dog CL(G): ‘wag_tail’ CL(V): ‘walk’ stroke
‘Gianni arrives at home. His dog wags his tail, so he (Gianni) walks toward him and pets him.’