https://en.wikipedia.org/wiki/Eknath_Easwaran The author was an english translator and the good thing about the German language is that it is divers. For a reason it's called the country of the poets and thinkers lol.

In the end it's all a translation and just words. If one wants to get to know the message they will, no matter what language they speak. The Upanishads are not the Vedic rituals so it might be less tragic if some words are missing. It's a summary anyways but my first contact with them. :)