Relational vocabulary plays a foundational role in cognitive and linguistic development and in enabling autonomy, participation, and joint action. Despite its significance, relational vocabulary remains underrepresented in AAC research and practice, creating a critical gap in resources and intervention strategies. This dissertation foregrounds conversation, sensorimotor experience, and joint-action as pivotal mechanisms for teaching relational vocabulary to children who communicate with speech-generating devices (SGDs). By integrating theories of language acquisition and embodied cognition across three studies, this dissertation explores an AAC intervention paradigm that grounds language learning in action-driven, socially mediated contexts.The dissertation includes three connected studies that collectively advance an action- based approach to AAC intervention, focused on relational vocabulary. The first study highlights the importance of relational vocabulary for AAC users and exposes gaps in current practices for vocabulary selection through an empirical analysis of available resources. In this study, I propose an additional approach for vocabulary selection in AAC that emphasizes direct engagement with relational concepts and language for directing actions. The second is a conceptual paper that examines conversational recasts and self-repair—two mechanisms of interaction that drive language acquisition—as pathways for aided language learning. It positions children as active agents in their linguistic development, advocating for explicit prompts to encourage SGD- mediated output and self-repair in conversation-based interventions. The third study is a design- based research project that moves this dissertation from theory to practice. This final paper introduces Building Relational Vocabulary Together (BRVT), a theoretically grounded instructional tool that situates relational vocabulary teaching and learning within collaborative joint-action. This study evaluates BRVT through semi-structured naturalistic intervention sessions with two students who communicate with SGDs. Collectively, these studies advance AAC intervention research, offering both theoretical contributions and practical innovations for teaching relational vocabulary through an action-oriented approach.