ABSTRACT
Variability in subject expression has been a widely studied phenomenon and is the focus of a considerable body of research in both native and second language (L2) grammars. Crucially, the production of L2 Spanish learners, both written and oral, has been investigated in depth with a view to understand how they use referential expressions (REs) like null and overt pronominals i.e. what has been traditionally called anaphora resolution and other REs such as lexical noun phrases, as well as which factors constrain their use in real discourse. Subject expression is an essential defining property of human languages. Languages can be subdivided into null-subject e.g. Spanish, Italian, Greek, Arabic, or non-null-subject languages e.g. English, French, German. Apart from the number of activated antecedents, their gender can also influence the choice of REs in subject position.
