Johnson 2004 - CDLI - UCLA

3.1 Presupposition and assertion, topic and focus
Prior to delving into the correlation between topic, focus and presupposition, I take a
moment here to review the basic meaning of the terms presupposition and assertion and
also to establish some fairly broad correlations in their usage so as to orient the reader to
subsequent discussion. In everyday use, the term presupposition is typically used to
describe the part of an utterance that the speaker assumes his or her interlocutors would
agree with without any argument (the following examples from Saeed 2003, 101):
(1) a. Her husband is a fool.
b. She has a husband.
(2) a. I don’t regret leaving London.
b. I left London.
In each pair of examples, the assertion of the first sentence by the speaker presupposes
the truth of the second sentence in each pair. In (1), the speaker and the interlocutor must
mutually acknowledge that the referent of she has a husband—only when both speaker
and interlocutor are in agreement about (1b), can the speaker go on to assert (1a).
Likewise, it would be difficult for someone to regret doing something like leaving
London as in (2a), if he or she had never left the city in the first place as in (2b). In
languages in which topic and focus are explicitly marked, presupposition and assertion
are, for the most part, mapped directly into topic and focus. The topic of a clause is quite
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