On this website only English can be used, however in your magickal practice you can use any language that you feel comfortable and connected with.
Ideally it should be a language that you know thoroughly and feel comfortable using, or you may find that in reality you are saying something quite different to what you think. But if you feel drawn to use a particular language in your practice then you can, see what results you get from it.
In short. When a person conjures, with words of power - he puts energy in one or another task / goal. Emotions are the same - this is still that energy. Faith and concentration are the basis of everything. How to say ... "voice" - this is what helps to give confidence and strength to "thoughtform" - this is when the words sound in understandable language.
In short, the meaning is not in the language itself. And in such details as: intention, faith, concentration, visualization, desire, emotion, etc.
And, again - how is the magic effect limited? - The strength, knowledge and experience of the sorcerer / magician.