[Unit experience] What are the effects?

[Brave Brave Sir Robin]

Training relates to how a unit lines up. For example, hoplites would be trained, falxman untrained. In Vanilla, peasant was also a level for, aptly enough, peasants and units like wardogs and gladiators.

Discipline is how well a unit reacts to morale shocks such as, scary units, fire attacks, compromised flanks, and units emerging from hiding as well as general attrition through melee.

Edit: There may also be a highly trained level which would probably be applicable to hoplites, phalangites, and other units that rely on keeping formation who are professionals. I haven't checked the edu lately.