the differences of pronunciation and tone bring about few of problems
because the gov. established lot of rules to reduce it
and that the controllers' spoken english was improved especially in big city
troubles come from the customs sometimes
for example , we use the "hold position "to stop the aircraft,
but in america, "hold in position " seems to be the clearance for "line up"
at the holding point ..."holding position "or "hold in position "? cofused..