Hi Carmen: I think it's helpful to "assist" the guest by providing a list of current topics or areas of emphasis you want to make sure get covered. I don't mean telling them how to say it or portray it - that's the benefit of a fresh face and different perspective. I think when the speaker is cued into current topics, the students will realize what the teacher and school is emphasizing is realistic, and the discussion will reinforce current topics, more so than just some unrelated remarks. Regards, Barry