Within the context of a public school district at the middle and high school levels, this study investigates the problem of world language teachers struggling to shift their instructional practice to promote communicative competence through a curriculum focused on student proficiency development in the target language, and addresses the problem by using a study group and collaborative curriculum writing model. Although previous research has supported the rationale behind a shift in instructional focus in the world language classroom, this study is novel in using curriculum design as a model for professional development. Teachers' beliefs about curriculum were surveyed to ascertain if a shift in these beliefs occurred as a result of participation in the study. Seven teachers participated in the study, representing teachers of Spanish, Mandarin, and Latin. Using mixed methods, qualitative and quantitative data were collected through a series of three surveys, and supporting documentation in the form of the researcher's journal, meeting notes, and sample units was collected. Results indicate a positive shift in teacher beliefs about curriculum, with the model implemented being perceived as an effective and positive experience, and final curriculum units created as a result of the study document a shift to a thematic-based curriculum that makes purposeful communication a central focus. The model could be replicated in similar districts to develop the ability of world language teachers to revise curriculum.