Elizabeth- I would like to add to your post that I have found with all of the students I have taught that musical expression is just as much a part of technique as hand position, finger motion, velocity, etc. Students who are learning the basics of musical expression don’t have the technical control to execute smoothly what they are trying to do. So the first few times they make a crescendo, the first few notes are soft and then suddenly everything gets loud. The same thing goes for making a ritard, where the first notes in that section are at one tempo and then suddenly they switch to a slower tempo. I also find that they have just as hard a time controlling these changes over varying lengths of time. For example, a crescendo can take place over 4 measures or over 3 beats, and the student has to learn how to do each one as a seperate technical issue. Their first attempts are more than likely going to make all crescendos the same length and the same change in volume. So I think initially the teacher not only has to impose a musical interpretation, but then teach the student how to execute each of the interpretative changes. Once the student has these techniques under control, then I try to listen for how that student hears the piece, how he thinks about the piece, and guide the interpretation rather than imposing something that the student doesn’t feel.