RTF in the States IS more slack. The term "Ready for departure" is the correct ICAO phraseology.
In the US - many pilots say "ready for take-off". The words "take-off" should only be used when acknowledging take-off clearance. The controllers there give "number four-cleared to land". This sort of practise is quite frankly dangerous.
AirFrance pilots speak in French on Charles De Gaulle approach while English is being used simultaneously-again..illegal and dangerous. (due Zagreb Mid-air collision in 1976) But we never learn!