>>715176416He could have been operation paperclipped aswell ww2 was basically 20 or so years ago by the time of tf2 and even just 5 years is more than enough time to get perfectly fluent in english if your actually trying.
And also heavy just seems like the type of guy who's actively scared of the idea of not clearly sounding like were he's from and is overall stubborn about shit which is probably why his english is still just "good enough to get by" levels despite probably knowing the mercs for atleast a few years.