Most of us that have had experience with ICAO and the speed at which they process change believe that the normal time to process a change is around seven (7) years!
About a decade ago, there was an ATC conference in Europe where many of the issues discussed on this thread came up. One rep from Europe asked why the FAA controllers did not use the ICAO standard phrases and what would be required to get them to change...?
The response from the FAA rep said it all.... "it would be easier to change ICAO" !
"Air China 5 - 81, have you been cleared to the ramp?"
The custom (for good reason) in many countries is to only use the word "cleared" when you have in fact been cleared to do something, and it is never, never used at any other time, and certainly not in a question that is open to interpretation, expecially if some of it is blocked out! That is only asking for trouble when it is a non standard phrase and you are communicating with pilots that do not have English as a first language.
An established culture is very difficult to change, and processing such change may take many years and much effort. But there has to be a will to do it.
Our American friends have come in for a bashing in this thread (and some of it deserved), but it is no different to any other English speaking country that might use slang from time to time... they just use it a lot and don't seem to think about the recipient.