These language learning CD's seem to be based on 2 main principles 1) Learner plus 1 The learner learns one new thing at a time. Knowledge is built one concept or technique at a time. Spaced repetition Although Thomas says at the start of each course that there is no drilling involved, there is a lot of repetition in the courses. It also seems to be spaced, in that intervals between repetitions are short at first and then get progressively longer. I have been trying to incorporate these techniques into teaching. One problem is that it is not always clear where students are, so you can't add just one thing, until you know what you are adding it to. Some students don't like repetition, although I know it is good for them, as otherwise they will forget. But some students lap it up, and like the idea of reminders, especially if they are getting stuff right on the 4th or 5th (!) go through. So it is an interesting experiment I am conducting.