This is how Paulo Napolitano put it:
Teaching focuses on making an individual learn the basic concepts and key points to perform a certain process. Teaching must be given in an environment that allows the student to make mistakes without causing any harm to the project or organization. The teacher will focus his or her communication on the concepts, key points, examples and exercises that the student needs to learn and practice to perform in the real world.
When I am teaching strategic planning to a student, one basic concept is “alignment” and a key point for alignment is that “all stakeholders must participate”. In order for the student to learn I give him one or more examples and exercises to practice. “Concepts, key points, example and exercises represents the basic structure of my conversation. At the end of the training I must be confident that the student understood the basic concepts, key points, and practiced enough so he can be released into the real world and become a practitioner.
Coaching occurs in the real world, the place where things happen. Coaching transpires during action! The coach’s expertise must be built upon an extensive experience implementing basic concepts and key points in different situations. As the practitioner starts implementing what he or she has learned, he or she will face situations that are unique, and most of the time, he or she will need to make adjustments. The coach‘s role is to help the practitioner adjust his or her performance based on the situation that he or she is experiencing and improve his or her efficiency. The coach will focus his or her communication on basic concepts, key points, identifying the situation, adjusting actions, performance, and lessons learned.