This landmark volume engages the lived realities of linguistic discrimination by naming and countering colonialingualism, an operating system that marginalizes Indigenous and minoritized communities in language education. The book defines colonialingualism as the privileging of dominant colonial languages, knowledges, and neoliberal valorizations of diversity, operating from ideology and policy to practice and outcomes. Spanning the epistemic and geographic Global South, chapters present case studies, narratives, pedagogical interventions, and curriculum and policy analyses. Together, they show how the system operates, informing a practical counter-practice toolkit for curriculum and assessment design, institutional change, and policy routes. The book recenters Global South and Indigenous epistemologies as sources of theory and method, advancing raciolinguistic perspectives and multilingual frameworks such as translanguaging and plurilingualism. Contributors mobilize Sumud and Ubuntu pedagogies, heteroglossic space-making, life-story and autoethnographic methods, place-based inquiry, and AI literacies to expose and counter the colonialingual ideologies sustaining native-speakerism, accentism, and linguistic racism within English language education and beyond. Ultimately, the volume demonstrates how minoritized communities resist, reclaim, and revitalize their languages and knowledge systems, and how programs and policies can be redesigned in accountable, pluriversal ways. It will appeal to scholars, researchers, practitioners, and postgraduate students in applied linguistics, TESOL, and language education engaged with urgent issues of linguistic and epistemic justice and decolonization.