Joshua Jones
When all is said and done, all's quiet and boring.
I think I understand what you are getting at, and it seems possible, but, to be honest, it is pretty ad hoc. Why would the language of an extremely advanced group of humans be one random Germanic language which is heavily influenced by quite a few other languages. Yes, it would make things pretty convenient for you, but it seems a bit of a stretch. And that assumes you can present it in a way that doesn't seem Anglocentric.Is it possible that if a ancient humanity existed and something causes them to regress back to the stone age humanity, then over thousands of years they re-evolve into us, modern Humanity...well, what I'm speculating is would it not be possible that the same species would over time return to what they were before. Most importantly, their language to. What I'm trying to say is, is it not possible that ancient humanity developed English then we as modern humans simply rediscovered the language without knowing it. Could that not be possible? I hope I've explained it right. I hope its not too confusing?
I think a more plausible way to go, at least in my mind, is that they are responsible for the massive, ancient increase of linguistic complexity, which to my knowledge has never been satisfactorily explained, by their language being the source language of the various language families. This approach doesn't give preference to one language, and connects their history to ours to solve a real world mystery.
Of course, this is your story; make it any way that sounds plausible to you. I just wanted to make a suggestion that sounds plausible to me.