Temporal information in natural language

Sammanfattning:

The subject of this thesis is temporal information; how it is expressed and conveyed in natural language. When faced with the task of processing temporal information in natural language computationally, a number of challenges has to be met. The linguistic units that carry temporal information must be recognized and their semantic functions decided upon. Certain temporal information is not explicitly stated by grammatical means and must be deduced from contextual knowledge and from discourse principles depending on the type of discourse.

In this thesis, a grammatical and semantic description of Swedish temporal expressions is given. The context dependency of temporal expressions is examined and the necessity of a conceptual distinction between phases and periods is argued for. Furthermore, it is argued that the Reichenbachian notion of reference time is unnecessary in the processing of temporal processing of texts. Instead the general contextual parameters speech time/utterance situation (ST/US) and discourse time/temporal focus (DT/TF) are defended. An algorithm for deciding the temporal structure of discourse is presented where events are treated as primary individuals.