Aspectual Entities and Tense in Discourse

Linguistic expressions form interesting patterns in discourse. In the domain of temporality, the morphemes of tense and aspectual viewpoint pattern significantly within a discourse. Shifts of viewpoint and tense are often associated with shifts of direction, and with the distinction between foreground and background. One important reason for this effect is that aspectual viewpoint and tense form closed sub-systems in language. In a closed system, choice of one term implies contrast with the other possibilities. The element of choice and its contrastive significance allows for more than one level of discourse meaning.