In all fairness, it’s possible last time Thor had to speak English on a frequent basis was in the 16th century, but then he’s spent some time here and he has Updated His Language Pack™ now

Hasn’t he not been speaking English the whole time and Allspeak has just been translating for him? So he’d say “if you keep fucking with me I’m gonna yeet you outta here” and it would come out “do I look to be in a gaming mood?”

This is what he was really saying all along, Heimdall just upgraded Allspeak