When one says "Do you want a cup of coffee?" he can mean:
- either an informative question — "Do you feel a desire to a cup of coffee?",
- or a polite offer — "I can make you a cup of coffee if you want".
What is the general name of this type of ambiguity?
I think it should be either semantic ambiguity or pragmatic ambiguity, however the examples I found for both of these types, for example this one, are unlike the above case.
Better references will be appreciated.
Best Answer
This is an example of Indirectness in illocution. In particular, the question
can be used as an indirect offer, rather than (or perhaps regardless of) its informational request sense. Indirectness is pragmatic. That is, it has to do with illocution.
But it's relative; all language is symbolic, and therefore not direct; some might call it duplicitous, in fact. That is, by contrast with placing a cup of coffee before the addressee, saying anything counts as indirectness. So one must compare the prototype illocutionary force of a construction (usually to assert, to question, or to direct) with its actual effect in context.
There are special conventions for how to do this in English (as in any language). Most of them spring from Grice's Maxims.