Lance touches on something that has lain at the heart of my questions about teaching methods. This is purely personal. My experience is that it is not the number of repetitions but the context that allows a form – be it a word, grammar, even a phoneme like the single tap vs trilled r of Spanish – to “lock in”. This is very subjective, it is something I feel inside, this “locking in”.
Why so many repetitions? To give the form a chance to occur in a context where it will lock in. That may be 12 times or 80 times. So much has to do with the learner’s attention level, personal background, etc.
And all that flies in the face of the current demand for total uniformity in our education system, a uniformity that serves our benevolent overlords rather than our students.
The term “Net hypothesis” came up on the thread, coming from early Krashen/Terrell writings and that is exactly what I am getting at in this entry: we don’t know when the “locking in” will occur (or even why), so we keep throwing L2 at the learner either naturally, in the course of interacting with native speakers, or unnaturally, in the classroom via tprs, knowing that the learner will select out what he “needs” in the way of i+1, understanding enough of the surrounding material aka input to follow along. VanPatten refers to this as “uptake”, I believe, that part of the input that you take up or lock in, in my terminology.