This study examines whether the process of interacting in a second language, versus observing others interact, may differentially affect learner's awareness of language. This study involved 26 university students of intermediate-level French. Two experimental groups, Interactors and Observers, engaged in three sessions of dyadic task-based interaction. The tasks elicited use of noun-adjective agreement and the passé composé. Although the Interactors provided little feedback to one another, subsequent stimulated recall interviews suggest differences between groups as to what they were thinking about during interaction, with Interactors paying more attention to language form. The results suggest that active language production itself (rather than passive observation) pushes learners to think about how to express meaning in the target language, and to draw upon explicit knowledge of the language. The findings contribute to understanding roles of output in second language learning.