Redefining the norms: an interdisciplinary perspective on language testing in multilinguals with acquired and progressive neurogenic disorders.

Accurate language assessment is essential in clinical and research contexts. However, most assessment tools and questionnaires have been developed within monolingual frameworks, overlooking the particularities of the vast multilingual population and, thus, often leading to misdiagnosis and inequitable care. Here, we examine the limitations of monolingual-centric approaches to language testing in multilinguals with acquired and progressive neurogenic disorders and explore the implications of multilingualism across linguistic, cognitive, neural, clinical, and sociocultural domains. We also address the need for technological innovation and theoretical refinement to better accommodate linguistic diversity in healthcare. Ultimately, we advocate for a nuanced, equitable, and culturally sensitive model of language assessment that reflects the realities of multilingual populations by accounting for their diverse linguistic repertoires, cognitive trajectories, and neural profiles. This model integrates valid, adapted tools, inclusive normative data, and context-appropriate testing practices, with particular attention to under-represented and typologically diverse languages.