It is a hallmark of natural language use that the way we talk about something reflects how it is represented in the mind of our conversation partner. This thesis studies the use and cognitive processing of referring expressions like one in comparison with other expression types in spoken Danish. The cognitive status of referents in other people’s minds can be understood in terms or referential givenness. The common view of givenness is that it constitutes a one-dimensional scale or continuum of (...) cognitive prominence. In opposition to this view, the present thesis assumes that givenness is partly composed of the dynamic referential features of accessibility and identifiability, two fundamental dimensions of givenness that are essentially free to vary independently of each other. A small corpus study of spoken Danish shows no differences between referent accessibility in indefinite and definite pronominal forms. Furthermore, referents of definite and indefinite forms clearly tend to differ with respect to identifiability. An experimental eye-tracking study provides evidence that there is no difference in the timecourse of the initiation of anaphoric reference resolution processes between expressions differing in definiteness marking and lexical explicitness. It is also shown, however, that the referential commitment of pronouns---both indefinite and definite---lag behind that of full noun phrases. Finally, an explorative dyadic eye-tracking study suggests that the moment-by-moment activation of referents in both speaker and listener vary as a function of lexical explicitness in indefinite forms. This result is consistent with the assumption that givenness differences associated with accessibility marking generalize to indefinite forms. All of these findings provide support for the new view of givenness proposed in the thesis. The dyadic eye-tracking methodology eventually arrived at in the thesis proves that it is possible to study language processing in unscripted, relatively natural dialogue in both speaker and listener simultaneously, and that interesting results can be obtained that are well worth the effort. (shrink)