Arcana
Pure mages speak in runic letters. It grants no power; it shows what you gave yourself to.
Arcana is a privilege written for characters who gave themselves entirely to magic.
To use it you must have no combat skill at all, and Magery, Meditation, Anatomy and EvaluatingIntel must all four be above 98.
If you qualify, you turn it on and off from the Arcana line on the character information screen, and what you say appears in runic letters. The choice is kept on your character, so it survives logging out.
It closes itself when the terms break
Turn Arcana on and then learn a combat skill, and the privilege drops. The check runs at the moment you cast, so a mage who has taken up the sword cannot keep speaking in runes.
Arcana grants you no power. It only shows what you specialised in.