A couple of years ago my neighbours came over with their 14 year old son. They put him in the local state school, but he was held back a year to allow his language skills to catch up with his academic ability. As far as I know he hasn't struggled at all and always told me that he enjoyed school. He was speaking at a good standard within 6 months and went on to do further education aswell.
I don't know too many expat kids around my way, but it wouldn't surprise me if for every 14 year old that adapted quickly and easily, there was a 9 or 10 year old that struggled. I would agree that it depends on the induvidual.
