"English doesn't 'borrow' from other languages: it follows them down dark alleys, knocks them over, and goes through their pockets for loose grammar and valuable vocabulary." -- James Nicoll
Having learned German as a second language, I can attest to the fact that speaking English has been enriched by German loan words. A lot of what makes English such a great language is its fluidity and adaptability. For example, the livestock words borrowed from French (beef, poultry) didn't replace the Old English words (meat, chicken). They just gave us alternatives. Now I realize why we have so many synonyms in English. I always thought it was primarily because it was just to express similar ideas with slightly different meanings, but sometimes the real reason is the melding of different languages.
It's a very interesting topic and good intellectual "fun" as long as one doesn't become too insurgent with it. An illustration might be the introduction of the German word Ausgangstext ("initial text") into the vocabulary of New Testament textual criticism. For some, the term has replaced the more traditional "original text." Generally speaking, when a word falls out of use, it's largely because it has outlived its usefulness. Scholars are therefore always coming up with neologisms -- often from German -- to move us "past" the past and into the future. Think Weltanschauung for "world view" or Heilsgeschichte for "salvation history." As a guy who teaches New Testament, I must say I find Ausgangstext a little disingenuous. Yes, it's punchy, even a bit scholastically elegant. But if all you mean by the term is that version of the text that was ultimately approved by the author for eventual publication, then I think I prefer to stick with the expression "original text."
I'm not against neologisms. I think it's great to have both native words and long loanwords. "We were slaughtered" and "We were decimated " feel very different despite their similar meanings. The soldier says the former. The commander says the latter. But the choice is not insignificant!
That's my thinking for now.