[quote=@Silver Carrot]
Do we have a teacher specifically for a class about controlling your elements?

Failing that, I'll do English.
[/quote]

Be an English teacher. You're also (assumed to be competent elemental user since you teach at the Elemental Academy) qualified to give either group or individual lessons about controlling the element that you control. Since we don't have any Avatar-style wielder of all the Elements, any Elements that lack a teacher are holes we would conceivably need filled. But yes, to answer your question, Jordan Manilow can teach Earth students for example, and Catherine has been teaching Air students, etc.