It is not just about different languages. Sometimes it is idiom.
Occasionally I have no idea what a New Yorker is saying to me and they have less of a clue about me.
It is a question of what you expect the other to say in a particular situation - like 'on the right' was not understood by our cab (taxi) drtiver, who was listening for 'take a right' - and we referred to a flat when we should have said 'apartment'. All this stuff makes a huge difference as to whether you have to turn the car round and change direction...
Waiting for a tube ("subway") in London we have to 'Mind the Gap'. In NYC we "stepaside".
I love how technology allows us to put these items side by side.