Just to pick a nit: English, as you say, comes in part from a West Germanic language (namely, Old English). Old Norse is a Northern Germanic language. Old English was influenced by Old Norse due to Viking invasions. Old Norse evolved into the modern Scandinavian languages (Icelandic is the closest to Old Norse), and Old English of course evolved into Middle and then Modern English, picking up a lot of French via the Norman Invasion (who were themselves descendents of Vikings (just sayin')).
And of course, all these languages had many dialects. So there's not "one" Old English or Old Norse, etc.
I was going to assert that the Asgardian language would more likely be closer to Old Norse, given the landing at Toensberg depicted at the beginning of Thor1. But Vikings had had contact with the British Isles prior to 965 CE. So maybe you could say there were earlier contacts with the Asgardians, in which case it could have been either in Scandinavia or elsewhere.
BTW, in the Thor1 script on line is this exchange:
So, how can you speak our language?
Your language? Ha! Silly girl, you're speaking ours.
A while back someone (maybe not on this forum) asserted that people from Australia tend to do poor British accents and pointed to Hemsworth as an example. My thought when I read that was that one could instead think of him doing an Asgardian accent
Thanks for posting this. I enjoy this kind of stuff too!