Although standards for world language education have brought forth a needed shift in instructional practices--moving from traditional to communicative, proficiency-based methods--research suggests that many teachers have yet to modify their practices. This study follows three teachers at the K-12 level who attended a summer professional development event, intending to implement proficiency-based practices when returning to their classrooms. Teachers were observed and interviewed throughout the course of the school year to examine their experience when attempting to implement the proficiency-based practices, and the factors that propelled them toward or discouraged them from implementing these practices. Results showed that concrete, surface-level practices were more easily implemented than those that required deeper understanding. School and program leadership emerged as an important factor in each teacher's likelihood of experiencing success.