The relation between person and epistemicity has been a topic of investigation throughout the humanities, including linguistics, but has mostly been focused on how conceptualisations of these two notions overlap, or diverge. This paper reviews some of these conceptualisations, but also adds a finergrained picture of how they intersect in the world's languages. Purported categories such as egophoric marking and lesser known expressions such as non-selected arguments (i.e. ethical datives) are compared to evidentials and modals from a synchronic and diachronic perspective in order to explain how the roles of the speech-act participants as specific arguments relate to their respective function as epistemic authorities. The aim of the paper is to introduce separate contributions relating to such systems as they are found in various parts of the world.