Presuppositions in Spoken Discourse

Accommodation and Presupposition
seems to be backgrounded to another main message, and even at a logical level the
characteristics associated with presupposed information, e.g. projection from nonentailing
contexts, etc., point to it being backgrounded. For example, Asher &
Lascarides (1998b), take this into account in their analysis of presuppositions by
generally treating them as rhetorically related to the discourse by Background or
Defeasible-Consequence. By backgrounded I mean that the presupposed information is
not the main point of the utterance, but rather supports the main point. If known
information is made activated by being presupposed, it should be serving a
background function to some other new information. If the presupposed
information is hearer-new, it should also be serving a background function to some
other new information.
By examining the context in which examples of accommodated
presuppositions were used, we can look for clues as to whether or not the
presupposed information seemed to be new information that the speaker intended
to introduce, or known information that the speaker intended the hearer merely to
recognize, retrieve, and or treat as currently salient, etc.
There are two types of evidence that have been discussed as clues to the
information status of presupposed information. The first is the presence of
prosodic prominence, discussed in Delin (1995). Delin considers pitch accent
within the clefted constituent in it-clefts as signaling that at least part of the
information presupposed must be hearer-new, and she uses this as her main
evidence. The second type of evidence is length, pointed out by Prince (1978) in
her study of information-bearing it-clefts. Length signals informativeness, and a
very long sequence is taken as evidence that the information is new.
I will mainly rely on another type of evidence, though I will refer to the
other two just mentioned. I will concentrate instead on the way the speaker has set
up his message, the message used, the role of the message with the presupposed
information in the discourse and the hearer’s reaction. If the presupposed
information is the main point of the utterance, being what I would call foregrounded,
then I interpret it as being hearer-new as long as there is not other evidence to the
contrary.
The hearer’s reaction is actually a kind of secondary evidence that only
suggests whether the presupposed information was totally new or known. His
reaction may however confirm or deny the speaker’s assumption. If it seems that
the speaker is introducing information that he seems to be treating as hearer-new,
and the hearer responds with something like “But I already knew that,” the
presupposition was still being used to introduce what the speaker believed to be
hearer-new information. For this reason the use of terms like hearer-new, and
hearer-old can sometimes be inadvertently misleading because we cannot give a
unit of information a neutral “tag.” Instead we have to discuss hearer-new
information from the perspective of the speaker, and hearer-new information from
the perspective of the hearer. It is the former perspective that tells us something
about the functions speakers believe they can use presuppositions for. The latter
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