From ThornsWiki

Spells or Conversations are inscribed in Monite, which in its written form resembles "chicken scratches". They can be read up-to-down or left-to-right.

Writing a spell usually takes many years of study and trial. It is not a requirement among galdori to have written a spell, but to have done so is a mark of great knowledge and prestige (akin to a Master's degree). A galdor who has written more than three spells gets the honorary title of Magister. The Professors at Brunnhold are famous for having written enough spells between them to fill a small library of grimoires.

Because spell-writing is an intimate experience, the author of a spell gains the ability to cast the spell without speaking.

Once a spell is written and inscribed, it is subject to a barrage of tests which are performed by top-ranking galdori, either at Brunnhold or a similar institution. Once the spell has been checked carefully for any mistakes and it is confirmed that the submitter can perform the spell silently, it goes on the books, taking either the name of the author or a more general name that refers to its use. (For example, the spell of Terror comes in seventeen different incarnations: the root spell, and sixteen variations written by various sadists.)

There are several libraries of grimoires scattered across The Ten Kingdoms, but it is generally accepted that the Library at Brunnhold is the best, containing over a million volumes.

Please see Casting for more information.