 As Tirrell's research progressed, she began to integrate her inferentialist approach with speech act theory, and Wittgenstein's basic concept of a language game.Tirrell's research started in the United States but later branched in to other regions of the world, now focusing on Rwanda and the surrounding region.Focusing more on 'speech as action' than she previously had, and working on explaining the action-engendering power of certain deeply derogatory terms led her towards studying the role of changing speech practices before and during the Rwandan genocide (which then led her to participate in discussions with prosecutors at the International Criminal Tribunal for Rwanda in Tanzania.)