Renewable Energy Communities (RECs) have emerged as central instruments in the European Union’s strategy for the ecological transition, promoting decentralised energy production and local sharing. This contribution proposes a comparative lexical analysis of four key regulatory texts, two European (RED II and RED III) and two Italian (Legislative Decree 199/2021 and CER Decree 414/2023), to explore the semantic evolution of the regulatory language related to RECs in the different levels of governance. Using the IRaMuTeQ software, co-occurrence graphs and Sankey diagrams were generated to map the most frequent words and their contextual relationships. The results show that European directives adopt a more institutional and strategic vocabulary, oriented towards principles, governance and long-term objectives, while Italian regulations focus more on practical implementation, incentives and administrative procedures. Standard terms such as energy and renewable confirm the alignment of objectives, but lexical divergences highlight differentiated priorities: words such as member, state and union are predominant in European texts, while PNRR, incentive and ministry are central in Italian ones. Such evidence underlines the importance of language mediation between policy levels and suggests that urban planning can play a bridging role between strategic intention and local operations. The analysis contributes to the scientific debate on RECs by offering insights into how regulatory language frames the energy transition, with implications for the planning, governance and practical implementation of energy communities.