One particular member of my flying club is German, but living in the UK. He learnt to fly in the UK, and has a CAA-issued JAR license.
He visits Germany regularly, and thought about the possibility of hiring an aircraft whilst in Germany. One of the reasons why he hasn't done so yet is that, despite German being his mother-tongue, as he puts it "I don't know what the German for 'downwind' is!"
Admitedly that's not the only reason he hasn't yet flown in Germany, but it further demonstrates that English is not the universal language.
FFF
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