"Wizards are not sorcerers," he says with a sigh. Like he's had this conversation before and he finds it tedious to explain the difference.

"The natural magic of this universe is chaotic. Mercurial. It shifts and changes which is arguably in the natural of all magic but the energies here in particular resist control. I am drawing on the energies of my home universe to cast magic but the magic here interferes with many of the spells I know work back home."

Which is surely the sort of explanation that this young man wanted when asking that question.