The rules state that there must be a common language to teach something. How high do those scores have to be.
For instance, suppose the teacher has a native language of Greek and an Ability Block with languages, and the student has a native language of English and a Greek of 2. Could the teacher teach the student Greek? At what point is the student have a high enough Greek score that the teacher could teach something else besides Greek, say, Craft: Glassblowing?