This article analyzes multilingualism from an intercultural perspective, focusing on the political, cultural, and social dimensions that shape language use and revitalisation. Through a comparative case study of Peru and the Basque Country, it explores how multilingualism is supported or hindered by institutional policies, cultural practices, and social dynamics. The study’s primary contribution is the development and application of a functional analytical framework grounded in the political, cultural, and social dimensions, which it then operationalises through three application domains (education, translation, and identity). This framework is analysed using a systems-thinking approach – specifically the ‘Growth and Underinvestment’ archetype – to model and visualise the dynamic feedback loops essential for language revitalisation. Peru represents a highly multilingual country with endangered indigenous languages and limited policy support, while the Basque Country illustrates a more successful revitalisation model with strong institutional investment. The paper incorporates foundational frameworks, such as Fishman’s theory of reversing language shift, to propose a flexible model for analyzing multilingualism in diverse contexts. The findings underscore the need for coherent strategies aligned with local realities and a long-term intercultural commitment to linguistic diversity.