At Shodokan Honbu you are taught to teach almost from the beginning.
The usual situation is a static senior line and a rotating junior line with sempai expected to help their kohai progress.
Every class there is a portion reserved for grading preparation where you tend to be matched with someone two grades above or below you.
Sure you get the talkers (I was one - go figure) but eventually you want to get some practice in yourself and learn that correct one or two things and then get down to it. for some it takes a little longer to figure out and strangely I have seen people getting called on for not correcting as much as overcorrecting.
The overall atmosphere has a very low level of chatter. Most of the correction is by example anyway.