I had the same issue while language was set to DE-DE. Changing it to EN-US solved the issue. ATC speaks now clear English and not a single Denglish word 
Of course, complete game is now in English but this shouldn’t be a problem for you.
I had the same issue while language was set to DE-DE. Changing it to EN-US solved the issue. ATC speaks now clear English and not a single Denglish word
Of course, complete game is now in English but this shouldn’t be a problem for you.