In this chapter, I discuss how the discipline of International Relations (IR) has come to understand the role that language and emotions play in diplomatic negotiations. I provide an overview of IR’s major theories. On the one hand, language and emotions have been much neglected among proponents of neorealism, neoliberalism and rationalism - commonly considered the more “American” approach to IR. The exchange of words and bodily (including emotional) cues in diplomatic negotiations is often dismissed as irrelevant - as the saying goes, “talk is cheap” - or assumed to be epiphenomenal to some larger forces at work (e.g. the balance of power and interest among interlocutors). However, scholars of constructivism (including normative constructivism, and the theory of communicative action) have in the past two decades sought to overturn such “nihilistic” understanding of diplomacy. They argue that, as in all social interactions, meanings are created because of the intersubjective social structures that leaders and diplomats share. Finally, and more recently, a number of scholars have leveraged insights from cognate disciplines - notably social psychology, cognitive science and neuroscience - to better substantiate the emotional dynamics that transpire in diplomatic negotiations. In the conclusion, I highlight a couple of directions for research in the future.