Sylvie Noël has a basic suggestion on How to get better information from an expert:
[I]f you want to understand your local expert, tell her how much you already know about the subject. That way, she can adjust her vocabulary to your needs.
Just as in any other conversation, the more context that is shared between the participants, the more likely they will be able to understand one another. This reminds me of Rules of Asking Others to Share Knowledge that I borrowed from Bruce Karney.
This also relates to expert systems and the need to somehow translate what the expert knows into heuristics that can guide non-experts through the problem domain. Imagine how much better the "answers" of such systems if they somehow knew how much the user understood about the problem domain. Sylvie's comment was spurred by reading:
Information About a Layperson's Knowledge Supports Experts in Giving Effective and Efficient Online Advice to Laypersons, by Matthias Nückles, Jörg Wittwer, and Alexander Renkl, published in Journal of Experimental Psychology: Applied, vol. 11, issue 4, pp. 219-236.
To give effective and efficient advice to laypersons, experts should adapt their explanations to the layperson's knowledge. However, experts often fail to consider the limited domain knowledge of laypersons. To support adaptation in asynchronous helpdesk communication, researchers provided computer experts with information about a layperson's knowledge. A dialogue experiment (N = 80 dyads of experts and laypersons) was conducted that varied the displayed information. Rather than sensitizing the experts to generally improve the intelligibility of their explanations, the individuating information about the layperson enabled them to make specific partner adjustments that increased the effectiveness and efficiency of the communication. The results are suggestive of ways in which the provision of instructional explanations could be enhanced in Internet-based communication.