Interlanguage grammars are complex and are shaped by a combination of general learnability issues such as transfer and generalization, and characteristics of the individual learner, such as motivation and degree of extroversion (Lightbown & Spada, 2013; Selinker, 1972). The individual factors may be particularly salient in classroom learning, where motivation plays an important role in language learning. The question is whether they also play a role in areas that are implicit, perhaps occasionally touched on by the instructor but not necessarily part of the curriculum. Furthermore, the relationship between the different factors may change according to the proficiency level of the learners. This paper will examine the interplay of these factors by examining the acquisition of subject and object omission in Portuguese as a second language. Unlike English, Portuguese is a null subject language. This is a property that is taught in the education system up to a certain point. What is not necessarily taught, however, is that the choice of when to drop or include a subject must follow information structure rules: if there is no topic shift or contrastive focus, subjects are omitted, if there is contrastive focus, the subject pronoun should be used. This is illustrated in (1) (Rothman, 2009; Sorace, Serratrice, Filiaci, & Baldo, 2009). At the same time, Brazilian Portuguese allows third person objects to be dropped rather freely, again when the meaning is recoverable from the context