In Urama, there are two clause-final particles, ka and ra, that encode a variety of both semantic and pragmatic meanings. While previous approaches have treated these particles as clause-type markers or evidential morphemes, this paper argues that one of these particles, ka, has another previously undocumented function in conversation: to mark speaker-knowledge and what the speaker assumes the addressee to know. We term these interactional uses of ka and ra. Functionally, the interactional use of ka follows from its clause-typing and speech act properties. Theoretically, Urama represents a language that has a grammatical strategy for tracking information in the Common Ground, which is close in spirit to evidentiality and clause-typing, but qualitatively different.