I've always wondered how it is possible that spells are not the same depending on the wizard's language. How I am to cast anything if I'm not saying the right incantation? Isn't there a global common name for each spell that every wizard should use? Well I think I found an answer and, frankly, I should have guessed it way earlier.
It doesn't matter what word you use to cast a spell: it's the intention behind the words that matters.
Magic is not something one acquires. It is a power running through the veins of some people, waiting to be used. It doesn't come out of nowhere: when a wizard casts a spell, he bends his own magic to his will. Understand this : it is not the incantation that summons the magic, it is the wizard's intention, his decision to use his own abilities to cure, hurt, make wonders.
According to Ollivander, a wand is just a way to focus a wizard's magic. It is an accessory -however powerful- to rein in the magic and make it follow a precise path. Words and spells are just the same: they are only anchors that help the wizard in the summoning of his power! And it works, especially for children, who cannot control the strength of the magic running wild in them.
Of course, I assume that it is easier to cast in you own language to grab the meaning of the spell. This is why Fleur Delacour will get the same red lighting when saying "Stupéfix!" as Harry Potter when he yells "Stupefy!": all of those spells, translated in other languages or not, are hiding the same goal. Wether somebody gets hit by "Endoloris" or "Crucio", if the caster intended harm, they will suffer all the same.
And this theory is reinforced by many other facts! (Yeah, I've thought it through.) Like: I was saying that a wand is just a way of conveying the magic, and not of producing it. As a consequence, wizards can borrow other wands to cast ; it will work. They won't get results as impressive as with their own wand, because of all the the-wand-chooses-the-wizard thing, but still: it's their own magic they're using, and not a magical artefact! (And so if I follow my line of thought, a Muggle couldn't do anything with a wand. Or just a little if the wand, you know, kept a little power, just like a electronic device. Wich seems... Kinda logical?)
Another example: wandless magic. Wizards no longer need a tool to focus their magic. Their will is enough to summon their magic and make it obey. Isn't that amazing? It shows that some advanced wizards no longer need help to control their power, they're getting stronger than that!
And finally, the most obvious and final example (because you know, always keep your most striking argument for the end of your essay): wordless magic. I mean. Do I even have to expound? In sixth year - so early, and I never thought of it ONCE- , Harry gets taught how to use his magic without the need of an incantation. Isn't that the ultimate proof to show that words are, actually, meaningless? A French wizard, an British one and a Bulgarian one could all cast the same spell without understanding one word of what's being said between them, because the final truth is this: it doesn't matter.












