The one (communication) that points to the truth most effectively for each type of person. If we want to teach by example we start with the words we use, and we won't stand for the misuse of words. If we are accurate and we ask or make the important points, much like you have done here by focusing on what mode might be conducive to change, it's a sharp, accurate thought, it addresses that which is very substantial to the conversation.

The method that most effectively conveys the truth (cuts to the bone) would be the then the best one at effecting or priming a change, so then it's a matter of sharpening our wits.