I have been writing poetry for a short time now, and many times I had the urge to use a word that isn't in the English language, but expresses my feelings in the clearest way.
Is english too trivial for poetry? When I think of all those great poems written in english, I doubt it. However, some words are more precise in one language than another, that's right. Help yourself where you find what you need. But keep in mind, that readers may not be as linguistically adept as you are.