They touch on that in the Dresden Files at some point, because different people use different words for the same kinds of spells. The explanation there is, in general, that magic is fueled by belief--the symbols and words mean nothing unless you believe they mean something. So the protagonist, Harry Dresden, uses Latin (or Latin-like) words for his spells, whereas a Hispanic wizard we meet later on uses Spanish words. Harry uses a staff and a rod for channeling some of his magic, whereas another female wizard uses jewelry to store some spells.
So the words work, in essence, because the person using them believes that they will work; same with items of power. (When vampires show up, it's not necessarily a cross that will repeal them, if the wielder doesn't believe in the holy power of it; likewise, other items they DO imbue with that kind of power will work, regardless of what they are.)