Language is a balance of precision and flexibility, and scientific dialogue across disciplines faces challenges in how terms are used and how phenomena, including language itself, are described and explained. Taking dementia as its focus, this article offers linguistic perspectives on causes of inherent difficulty with terminological exactness. Attention is paid to the interface between the positivist imperatives of clinical evaluation and the relativist interpretations that help make sense of uses of terms across contexts. Two types of reason are examined for why the language produced by people with dementia is sometimes hard to characterize and predict: the theoretical challenges inherent in analyzing the language of dementia and the social variables that affect how that language is manifested. The article concludes with the vision of linguistic research using corpus-based discourse analysis to underpin and catalyze communication-bridging activities in interdisciplinary projects, within and beyond the dementia context.