Nationality has nothing to do with that, it’s all about experience 
I am Russian too but I will tell apart an Australian from an Irish and a Londoner from a Scouser most of the time.
Also both the American and British voicelines sound super cringe to me:
“It would be easier if you just died already”
“You can serve your country in hell”
Sounds like something from a cheap 1980s blockbuster.
As far as I understand, these are, indeed, phrases from old Hollywood films about the war)
By the way, it’s funny: I started dividing my assembly by nationality, and realized that the Allies only have British stormtroopers) Apparently, after all, the British will have to run with the “Thompsons”)
As I remember, you’re a translator, right?
My major was translation and interpreting, yes. However, that’s not where they taught me accents 
Well, I think the understanding of accents came with experience.