A null argument consists in the omission of an argument of the verb. This phenomenon is quite frequently observed in LIS discourse. The arguments that may remain unexpressed are the subject, the object, the indirect object, and locative arguments. To illustrate, we show below an example containing two lexical verbs, take and accompany. Both of them are spatially modified to mark their arguments: take is a backward agreeing verb (LEXICON 3.2.2) showing agreement from the object to the subject, whereas accompany is a spatial verb (LEXICON 3.2.3) showing overt agreement from one location to another. If these four arguments can be implicitly understood from the context, they may be all omitted. For instance, in previous discourse, the signer might have provided the following details: his son is very busy with all his activities, he is at school until 3 pm and at 3:30 pm he has to be at the dance hall for his hip hop class. In doing so, the signs son, school, and dance_hall are associated with precise loci in the signing space. In the example below, the pre-established loci help the addressee retrieve the omitted arguments.
1take3 aaccompanyb done
‘(I) picked (him) up and took (him from school to the gym).’
As similarly observed in other null subject languages, meteorological predicates (SYNTAX 2.1.1.4) in LIS do not require an overt subject.
today rain
‘Today (it) rains.’
Overall, licensing of null arguments in LIS may be influenced by some linguistic and extra-linguistic factors, which will be discussed in the following sections.