Weapons are learned in much the same manner as Vocations. The limitation is that weapons have various maximum ranks (levels) which can be achieved, while other skills usually top out at rank 10. Magic spells gain improved chances of success and better strength when rank is gained in them also, and this is done on a spell-by-spell basis (e.g. character is a fire mage and has improved his skill to rank 6 in Fireball, but rank 0 in many other spells of his magic college which he considers less important).