Arcane Magic is perhaps the most well-understood form of Magic in the world, formed through intense study and the codification of a magical language of logic and of understanding material reality. It is commonly studied by Wizards under mentors or at arcane universities.
The Arcane language is an old project that has been gradually added to, and only minorly revised, throughout the course of History. It consists of complex characters with a special, completely unique meaning (hapax legomenon), which then can be combined in certain ways to create spells - or in some cases, modified. The language is believed to originate in the ancient form of the dwarven runic language, which itself is thought to have been inspired by the Skaldic language of Fenrunr.
The Magus in the High Tower famously warned that newer concordats (since the Draconic one) have complicated and messed up the foundations of the Arcane language, and that it is on the verge of breaking down for good.