Much has been said in various manuals and treatises about the combat of the short fencer against the tall fencer and also vice versa. These are considerations of note and need to be taken into account. What does not seem to appear all that often are considerations of teaching a shorter or taller student and how this may change the approach that the teacher might take. This is something which needs to be considered as this will affect how the individual will be effective with their weapon.
Being a taller person, actions are performed in a particular way, and tactics are appropriate to a particular method. These are not so much for a shorter person. Thus as a taller person who is teaching people who are shorter, these things need to be taken into account. This is vital otherwise we are teaching the shorter person simply that they will be less effective because they are shorter and cannot do what the taller people can do, and this does everyone concerned a disservice.
What is ironic is that most people assume that because taller people have the length that they have the advantage, this is not necessarily the case. If a person who is shorter than their opponent extends their weapon from their shoulder, they will be directing their point toward the target area of the opponent. If a taller person extends their weapon from their shoulder, they may be directing their point over the head of their opponent. By having to drop the point down, length is lost due to the change in angle from the right angle at origin to an acute angle. The same reason a person may safely stop-hit at the face while keeping their leg free from attack. This is also something that should be taken into account.
In teaching the height of the individual must be taken into account, especially if there is a marked difference in height between the trainer and student. There is little point in teaching a short person to fight like a tall person as they do not have the reach, and there is not much greater advantage of the reverse because then the taller person will not learn to use the advantage of their reach. Actions which rely on an individual being a particular height as compared to their opponent should be examined, as many of them will not be as effective, and in some cases effective at all when the fencer is shorter. It is at this point in time that the trainer needs to change tact to suit the student.
A cut delivered vertically designed to clear or at least block the opponent's weapon while striking them is an excellent attack and works beautifully when executed properly, when the fencer is the same height or taller than the opponent. When the fencer is shorter, the angles are changed. The sword will connect further up on the weapon and so will not have the strength to do the job designed and the striking part of the weapon is less likely to strike the opponent due to length. The result is that this technique is not as effective, if at all. The trainer thus needs to find an alternative, such as stepping off-line and striking the arm, or stepping off-line and coming upward and underneath to strike the flank. This is only one example, there are many more.
Both teachers and students need to take height differences into account, not only from the point of view of combat situations, but also from a teaching point of view. A shorter or taller student is going to result in different angles as a result of their height. These are going to have to be taken into account in their training, and some actions will have to be modified. A good teacher will look at this as just another challenge to be surmounted in the adventure of teaching.