Nope, it is best to do spells in the language you are most comfortable with and fluid in. Doing spells in other languages can have their purposes and add to the working. But if you do not have proper pronunciation you can end up messing up the words in which case nothing will happen. That or you end up accidently saying something other than what you intended to so things do not exactly go as planned. So basically, it can end up backfiring. So best to stick to your native language unless you are sure of your pronunciation and have a specific reason for it being in another language.