Contrast and retroactive implicatures: an analysis of =lku ‘now, then’ in Warlpiri and Warlmanpa

The clitic =lku in Warlpiri and Warlmanpa (Ngumpin-Yapa, Pama-Nyungan, Australia) has been previously analyzed as a ‘change of state’ marker indicating some proposition is false at an earlier time, and true at a later time. In this paper, I examine a number of uses of =lku, which require expanding and refining the ‘change of state’ analysis, in order to argue for a new analysis of =lku as a temporal and discourse clitic. The temporal function locates the event or state being modified by =lku in the temporal consequence of another event or state. This function interacts with lexical aspect, triggering an inference of the cessation of an ongoing state or event, if there is one, and encoding the inception of the state or event being modified by =lku. The discourse use of =lku frames new information which should be evaluated against the ongoing discourse. I also demonstrate some striking cross-linguistic similarities, showing that temporal morphemes commonly interact with discourse structure, just as =lku does in Warlpiri and Warlmanpa.