Presuppositions in Spoken Discourse

Chapter 5
(24) Sofia also baked a cake.
(25) John comes to the party too.
(26) a. Beth decorated the room and Sofia baked a cake.
b. Beth decorated the room and Sofia also baked a cake
(27) a. If the boss comes to the party then John comes.
b. If the boss comes to the party then John comes too.
(28) Beth baked a cake. Beth decorated the room.
(29) John comes to the party and the boss comes.
Given an empty context, both (24) and (25) would need to be accommodated. The
same utterance without the trigger might be able to be considered an expression
alternative. However, this won’t work with the above examples if we define an
expression alternative as updating the same input context and leading to the same
output context. Interpreting (24) without also means that you have lost the
information that someone else did something comparable to what Sofia did.
The only alternative is to introduce the presupposed information by assertion,
as in (26) and (27), so that the information that the trigger was going to contribute
is already part of the context. The problem with this solution is then that if we add
the presupposed information before the utterance without the trigger, then we have
changed the input context. There is no longer an expression alternative that will
need to be accommodated, because the use of the trigger in this new context will be
resolved by binding. And binding will always be a winning alternative to
accommodation.
The problem here is that we cannot construct assertional alternatives for the
presuppositions triggered by too and also unless we communicate the information
that would otherwise be accommodated first. As soon as we do that, we have
created an antecedent for the triggered presupposition. This changes the input
context which in turn changes the set of relevant candidate alternatives for
generation. Thus, if we define expression alternatives with respect to the input
contexts, there are no expression alternatives to accommodation for these triggers.
This predicts that accommodation is freely available for too and also. But this is the
opposite of what is claimed in the literature and of what we find in the corpus.
Note that the examples with too are therefore very different from the previous
examples with pronouns because in those examples there was both an assertional
and an accommodating alternative that could update the same input context in a
similar way.
On the other hand, if we loosen our definition of alternatives and say that the
input context doesn’t have to be the same at the exact time of the expression then
we can use this explanation to account for too’s behavior. Too doesn’t accommodate
well because speakers prefer to first introduce by assertion and then bind the
presupposed material to it. Because this alternative is always available, we never get
accommodation with too in naturally produced data and we as hearers find
examples where too has to be accommodated anomalous because we know the
speaker could have used a form which wouldn’t have required accommodation.
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