Presuppositions in Spoken Discourse

Abstract
Naturally produced examples of presuppositions in the London-Lund Corpus of Spoken
English are analyzed using the binding theory of presupposition (van der Sandt 1992),
which treats presupposed and anaphoric information in the same way. Presupposed
information is either bound to a discourse-given antecedent for its interpretation or
creates its own antecedent via accommodation.
The corpus data suggests that bound presuppositional expressions are used and
perceived similarly to discourse anaphors. Additionally, due to their richer descriptive
content, presuppositional expressions referring to abstract objects can fulfill more
discourse functions than their anaphoric alternatives, contributing rhetorical effect,
referring more precisely to discourse-given information, making conclusions explicit, and
serving a summarizing function. These results lend further support to the treatment of
presupposed information as anaphoric and confirm the need for a binding analogy to
explain their usage in extended discourse.
The corpus data also contains naturally produced examples of presupposition
accommodation, which provides an empirical base for the discussion of several
theoretical proposals related to the phenomena. Factive presuppositions are
overwhelmingly used to communicate information believed to be hearer-new. Previous
accounts of what licenses accommodation cannot be applied satisfactorily across the
board, and the data does not entirely confirm the proposed preference for higher levels of
accommodation. Based on the data, it is instead proposed that preferences for
accommodation at a certain level may be dependent on embedding and trigger type.
Finally, presuppositions strongly related to the context but still new cannot easily
be analyzed as binding or accommodation. Typical cases are so-called bridging NPs,
which are normally treated as dependent for their interpretation on a unique anchor.
However, as the corpus data shows, multiple anchors may be available. Also, consistently
applying current definitions of bridging to examples within a rich context generates too
many bridging relationships relative to interpreters’ intuitions. I suggest treating such
cases as licensed by the context rather than by a single anchor, and furthermore,
considering as bridging NPs only those that 1) introduce a new individual in the discourse
2) are related to the context through some type of inference and 3) are marked as
anaphoric. The result is a more homogeneous group treatable by a single method and is
more motivated on semantic grounds.
Key words: presuppositions, anaphors, spoken discourse, corpus study, binding,
accommodation