I'm gathering up ideas for a urban wizard story and i wanted him to use an alternate language for his spells. Would it be okay to do a rough translation of the spell and what languages would be helpful to use?
Latin is always good because it's familiar and it the words never evolve or change, because it's a dead language. Creating a language is a fun idea, but can be cheesy if the words are not thought out fully. Also, a spell can be casted by meaning, not word. Saying the words "Die" with intent of killing would summon the spell to do so. Same with "fly", or "disappear". But, that's just my opinion.
From my experience with fantasy books and shows, Latin and Old English are used a lot when it comes to reciting spells. You can also be unique and use any language you see fit, including making one up.
Often times you can use english as the base of the words in your spell. There's nothing saying you don't have to. However, you can't just say "open the door" and expect the magic to work. A key factor to remember is that magic was portrayed in rhymes. If you want a good example of this I say watch a few Bewitched episodes, or even read some old stories about witches.
You could try using the welsh langauge. It's rarely used and it looks mysterious. I even found a translater online. Try and guess what this sentence says: "Beth ydy 'r dywydd cara ble ach." Answer: What is the weather like where you are.
A warning for anyone using online translators: often the translation it comes up with will not have the meaning you were looking for because they translate literally, word for word. They have no way of judging the intricaties of language and context so you end up with funny translation errors at best and nonsense at worst. Use them with caution.
I guess you can use any language which seems archaic or mystical to the reader (as opposed to mundane and well-known). I believe Latin works so well because it has become connected to the mystical and supernatural through the Catholic and Orthodox masses, and also because older mystical and magical literature is written in Latin (as was most scholarly works), but it is still so well-known to the reader that they can guess the meaning of Latin words. If I made a magic system with oral or written incantations, I would either chose the speaker's own language, or a language traditionally connected to the type of magic. For example, if the magic system was based on appealing to the spirit world, I would choose Russian, a native American language, or some other language with a strong tradition of shamanism. If it was based on appealing to guardian angels, Latin or Greek would be appropriate. When making golems, Hebrew is the language of choice. If the magic was based on runes, Icelandic or an ancient Northern European language would fit the bill. If it was based on magical objects, helper spirits or drawing in sand, Arabic would be fine. In the end, I don't think it matters which magic system you chose, as long as it seems reasonably plausible to the reader.
I would even consider the possibility that you don't actually need to add in the spoken words at all. The wizard said something under his breath and Michael felt the stirrings of magical energy. or Michael watched helplessly as the wizard raised his hands, chanting something he couldn't understand. Of course, these are just samples of my thoughts.
That was a Salvatore-ism, to not use the words at all. If I remember correctly, people watched out for wizards when they began to "waggle" their fingers and start muttering. One idea I really like is two different factors in the execution of techniques in the Naruto anime. On the one hand, there can be hand symbols, ending with the declaration of the name of the technique (*symbol, symbol, symbol*..."Fire Technique: Grand Fireball!") Or another idea from the same technique as before, but focusing on a different aspect, the seals they formed with their hands had names (animals from the Chinese zodiac is what they used, I think) and there's at least one scene I recall where two fighting ninjas were performing a long sequence of seals and muttering the names of the seals (Monkey, Dog, Sheep, Dragon, Sheep, etc.) Perhaps something like this would work for your purposes? Then you don't have to rely on much real knowledge of the language you choose, but rather you just need to know the names of certain objects that work (like the zodiac animals, or you might choose objects from nature like Tree, Star, Cloud, River, etc.)
Personaly I just make up a word or words and such. I never expand on the language except to keep the magic connected with that word or words. But most of the time I even just don't put in a word at all. Sorta what Rhsexton said. I will have it mentioned that the character doesn't understand what the magic user is saying or just 'muttered under his breath' So its really just a combination of both of these.
The Dresden files books handles the matter in this manner: "X chanted in some personal variant of Sumerian, her voice high pitch yet powerful." Its effective and nice. Reading line after line of a language I cant read adds nothing to my reading experience. On the other hand it masterfully handled in the Harry Potter books as well when they do write the spells in a different language, but then J.K. Rowling is fluent in Latin, and all incantations is simple one world spells like "Lumos" and there just a dozen of spells used during 7 books.
Mystery is a matter of perspective. Where I live the road signs all have Welsh on them so I don't find Welsh the slightest bit mysterious. And I'm willing to bet that you couldn't say that right
