The purpose of this large-scale descriptive study was to investigate the impact of an implementation model designed to provide U.S. classroom teachers with the knowledge, skills, and resources required to provide aided augmentative and alternative communication (AAC) instruction to their students with extensive support needs and complex communication needs. We followed 49 students with extensive support needs and limited symbolic communication across 2 years in the classrooms of 53 teachers who engaged in ongoing coaching and professional development. At pretest, the students demonstrated an average of 15 of the 80 (19%) expressive skills on the Communication Matrix. Multilevel longitudinal modeling was used to analyze changes in scores over time. The findings suggest there was a statistically significant relationship between time and Communication Matrix scores, with the ends of each academic year associated with statistically significant growth at rates of 3.01% and 12.38%, respectively. Implications for practice and future directions are discussed.