@Lanfear
Spellcasting uses the power of True Words, which the creator god used to create the world. In the beginning, there were only True Words, and if one said the True Word for fire, there was a chance to accidentally create fire. The creator god made the world, looked at what he'd done, and called it "good". But for something to be "good", "bad" had to exist. And the creator god was unable to take back its True Words, and so evil was created. Evil gods killed the creator, and in that instance, life and death were born.
Mourning that terrible mistake, the god of knowledge created the "common language", words distant from the power of True Words, so such an accident could never happen again.
But anyway, the point is that even gods have to chant true Words and their chants to manipulate imagination and nature to their literal words.