it's because the scandinavians were isolated for most of history , and Germans have had contact to other civilizations for 2000 years before the Vikings already.
Also, German itself is an artificial language, after the Translation of the bible people needed to find a common language, since "German" wasn't a thing, people spoke all sorts of languages that sounded similar to one another but not mutually intelligable , and we still speak them today on a local scale.
Let me give you an example
" La' mi di ma'n Beispiel je'n "
" Lass mich dir mal ein Beispiel geben "
that was " Let me give you an example " in a German dialect , and then official (proper) German.
All i can say is that the german language is the best language for conveying anger i have ever heard. I want to learn it just so i can scream in german.
I remember our norwegian teacher telling us that the danish army that instructors would yell in german...
And then the teacher told me to simply yell something in german to prove the point