Immersion students' language abilities are generally characterized by strong receptive skills (listening, reading) and less developed productive skills (speaking, writing) when compared with L1 speakers of the immersion language (e.g., Allen et al. 1990; Cummins 1998; Harley 1992). In this paper we report results from a six-month mixed-methods case study of a fourth-grade Portuguese dual language immersion (DLI) classroom that had implemented a focus on language forms through noticing, awareness, and practice activities, with corrective feedback interwoven throughout the process. We discuss the evidence of immersion learners' emerging linguistic and grammatical competence as shown through a written pretest and posttest and pre- and post-interviews. Results indicate that the large majority of these learners do not yet show consistent nominal or verbal agreement in their speech or writing, although signs of improvement were observed during the course of the academic year with regard to nominal agreement. Additionally, we present evidence showing that these students tend to produce an extremely limited range of forms for each verb, with many producing only third person singular forms in the present tense. We end with suggestions on how to help immersion students develop stronger and more accurate productive skills.