The Investigation Report summarizes the findings of extensive research carried out within the AAC 4 Inclusion Project, focusing on Augmentative Alternative Communication (AAC) methodologies across Italy, Romania, Spain, and Türkiye. It includes an analysis of existing scientific literature, highlights best practices currently implemented, and identifies available training courses for socio-educational professionals in each country. Through a combination of literature reviews, surveys, and focus groups, the report captures operators’ skills and knowledge gaps, revealing specific regional needs, challenges faced by professionals, and highlighting common themes such as the importance of communication for social inclusion, the balance between personalization and standardization of AAC methods, and the critical need for specialized professional training. The insights provided serve as a foundation for the creation of practical guidelines aimed at enhancing the competencies of professionals supporting individuals with communication challenges.