As a signatory to the UN Convention on the Rights of the Child, which has been incorporated into domestic policy, Iceland has a legal obligation to respond to children's linguistic human rights in schools. Increasing language diversity is addressed in both policy and practice, informed by the inclusive education principles that underpin the ideology of the Icelandic school system. A thematic analysis of the perspectives of four school principals and four directors of school support services, working in four different municipalities, reveals tensions between stakeholders' understandings of children's rights, school responses to diverse languages, and state accountability towards children's linguistic human rights. Application of Tomaševski's 4As framework (availability, accessibility, acceptability, adaptability) suggests the need for increased human rights education and funding for local rights-based initiatives and monitoring. The study contributes to policy and practice aimed at addressing language diversity as a human rights concern.