Diagnosis and treatment of childhood language disorder has to rely on knowledge of what constitutes ‘typical’ development. In endangered, minority languages such as Irish, this is problematic: Bilingualism is universal, and language change is rapid, and language norms can be fluid. We will present a speech-language therapy perspective on linguistic diversity fostering bilingualism for all children, outlining processes involved in and infrastructure necessary for clinical assessment of minority language children, in the context of communication as a human right.