A teacher is supposed to guide the learner through a given curriculum. He is expected to play the role of a catalyst sometimes. Where new bodies of knowledge come in, a teacher is expected to disseminate knowledge to enable learners to absorb information. The term manager may not adequately define what a teacher does. Teachers give much more than what is expected of them. What do you have to say about role modelling, character building, discipline in students, taking over where the parent left off in the morning in surrogate style? Supervision falls short where the teacher has to be an active participant in the learning process. A teacher has to constantly motivate the learner to enable them to absorb content. Whatever a learner gains at the end of a semester is charged upon a teacher, who has to answer to the proportion of learners who passed or failed. The big question is What do managers or supervisors do? Do they do what teachers do? The answer is no. If teachers would manage students the way managers do their stuff, nobody would pass examinations or even want to go to school. Secondly, a supervisor lords over those who know what they are doing. Do pupils know what to do?
Teachers teach, supervise, manage, guide, goad, discipline, lead, demonstrate, motivate, reward, encourage, correct, chasten or chide. Somebody said teaching is a calling. I think they were right. A teacher's best reward is not the salary but the success of the learner under their charge.