Mithradites

If you can't, it honestly makes no sense. Connecting to the void is just that- connecting to the Void. If the student understands the element they wish to summon, any one who can connect to the Void could easily instruct them.

^ Precisely what Eileen said, although many times your connection with the void is done in the same way summoning and controlling different things from it is another thing in and of it's self. Taking something from the void essentially is what most if not all magics are based out of. Now, Air Evo basically invokes gusts of wind from the void and has a different way of being handled than say Earth evo, correct? They ways each are taught are completely different due to said substances being very diffrent from each other.

I could be mistaken however, but I'm pretty sure that's about it.