Probably the older idea of teaching is something like "I know something and I will tell you". That means generally that you should listen carefully and remember what I say. An alternative way of teaching is along the lines of "tell me what you know and together you and I will add to what you know and modify the parts of your knowledge that are incorrect, incomplete or out-of-date." That approach will involve more of you telling and me listening and questioning you.
These models of teaching emphasize oral language. We both need to be able to hear and understand a language. If we are in modern times, we will have textbooks and probably videos or movies that we can watch together. We both need to be able to speak in a way the other can understand.
If I am a young teacher, I may be so aware of my responsibility for teaching and doing that I will feel better and more dutiful if I stand in front of you and other learners, and explain what I know that I want you to know. If I am an older teacher, I may have given an oral presentation on the topic many times. It may be a relief and more fun for me to listen to you tell what you know and what you think seems right to expect from a learner who has learned the subject we are working on.
Most of the schooling I am familiar with requires a learner to pass some sort of test to show learning has taken place. Usually, neither of us pays much attention to how well you could do on the test without my teaching, how well you could do on the first day of school. An older teacher is often situated in a way that few of the learners know what is to be taught beforehand. As an educator, a citizen and a theorist, I am interested in what you know from my teaching and I am also interested in how long you know the material. I have read that police officers, and others, I imagine, need to be recertified on the firing range or the handling of unruly citizens resisting arrest. I have often wondered if I might be called back to my high school sometime to be recertified as knowing what was required for my high school diploma.
