Detent.
This is multi point mistake, but to say mixed languages isn't a factor is frankly bollox. Haven't read the report, but were the crew on day 5 and on the edge of FTLs? Was the latest METAR accurate and up to date? Do we know the techlog status etc etc
I do know that the LTMA controllers are very careful to speak super clear and be mindful if a pilot is not an English speaker, as are the Dutch and the Germans. Try ORD on a bad stormy night and that's a different ball game.
FK10