You'll find many old sources of magic offer spells in ancient languages, such as Hebrew or Latin. Often this was blended with Greek, French, German, or even Coptic. You must realize however that those who wrote these spells were intimately familiar with the languages, and spoke in a manner that offered meaning and energy to every word; magick, after all, is more than simple speech.
It is generally unwise to speak incantations you do not truly understand as part of any ritual or spell for the simple fact that you could be pouring energy into something that you only half understand, and will therefore most likely offer results that are unreliable at best.
As it says in the book of Abramelin, speak your native tongue within magick, unless you are otherwise familiar with the language, so that you are always certain of what you are saying. Particularly in magick such as this, where you intend to communicate with spirits.