Yes, that would be a possibility for controlling distribution of powerful spells, except that the Edict of Merlin explicitly doesn’t do that: you can’t speak the words because you can’t understand the writing. If you could read and speak the spell (and whatever else the spell requires) presumably you could cast it. (Otherwise Merlin needn’t have bothered making the texts unintelligible as well.)
Yes, that would be a possibility for controlling distribution of powerful spells, except that the Edict of Merlin explicitly doesn’t do that: you can’t speak the words because you can’t understand the writing. If you could read and speak the spell (and whatever else the spell requires) presumably you could cast it. (Otherwise Merlin needn’t have bothered making the texts unintelligible as well.)