A Computational Treatment of Sentence-Final 'then'

UK Abstract We describe a computational system which parses discourses consisting of sequences of simple sentences. These contain a range of temporal constructions, including time adverbials, progressive aspect and various aspectual classes. In particular, the grammar generates the required readings, according to the theoretical analysis of (Glasbey, forthcoming), for sentence-final 'then'. 1 Sentence-final 'then' It is possible to follow: (la) Emily climbed Ben Nevis in July. with (lb) Fiona climbed Snowdon then. This is interpreted to mean that each climb took place at some time within the July in question. Notice , however, that if we remove 'in July' from (la) to give: (lc) Emily climbed Ben Nevis. the sequence (lc,lb) becomes harder to interpret and sounds rather odd. 1 The difference is, of course, that we have removed 'in July' and there is no longer an explicit reference to a "time". We will call such an explicitly mentioned time an explicit temporal re-ferent (ETR). Thus, sentence-final 'then' appears, i We are not concerned here with the rather marginal reading, available to some speakers, where what is conveyed by (lc,lb) is that Fiona's climb follows Emily's. This corresponds to the "updating" reading normally associated with sentence-initial 'then'. on the basis of this and other examples, to require explicit mention of a time. Being able to infer a time from the description of an event is clearly not enough. We would expect to be able to infer readily from (lc) that there was a time at which Emily's climb took place. However, it appears that we cannot use sentence-final 'then' here to refer back to such an inferred time. In order to make sense of the sequence (lc,lb) without the ETR, it seems we have to be able to see the two events as connected in some way. Consider: (lc) Emily climbed Ben Nevis. (ld) She achieved her ambition then. which sounds fine, and: (2a) The children went to Wales. (2b) Fiona climbed Snowdon then. which is also perfectly acceptable. Note that in both these cases the second event is readily seen as connected to the firstgby the kind of discourse relation that has often been called elaboration. 2 Now consider: (3a) John went to France. (3b) Bill Clinton became president then. This sequence sounds odd, presumably because it is difficult to see any connection between the events described in (3a) and (3b). Consider also: (4a) John took the children to …