Sagarra and Herschensohn’s article examines English L2 learners’ knowledge of Spanish gender and number agreement and their sensitivity to gender and number agreement violations (e.g. *El ingeniero presenta el prototipo *famosa/*famosos en la conferencia) during real-time sentence processing. It raises some interesting questions that are central to both acquisition and processing research. In the following paper, I discuss a selection of these topics, for instance, what types of knowledge may or may not be available/accessible during real-time L2 processing at different proficiency levels, what the differences may be between the processing of number versus gender concord, and perhaps most importantly, the problem of how to characterize the relationship between the grammar and the parser, both in general terms and in the context of language acquisition.