How do we deal with ambiguous pronouns? One view would be that grammar provides constraints on pronoun assignment. But grammar by itself won't do this job all the time. Psychological factors (i.e., context, expectation) are also required.
"What does 'expectation' mean? At each point in a dialogue, both parties are already involved with various concerns and desires. These establish contexts in which each new word, description, or representation, however ambiguous, gets merged with whichever short-term memory best matches it.
How can speech be designed to be easily received? By basing it on the properties of the speaker's minds, and assuming that the listener's mind will have similar properties.
NB: How might this relate to work on pragmatics, a la Grice? Do researchers on language context view shared mental properties as being part of what they do? This reminds me too of some work on creativity, in which the aesthetic process involved reconstructing (in the appreciators mind) the representations that were originally constructed in the artist's mind -- the name of the author of that stuff is escaping me right now!!