Missing the point?
Seems to me that if someone calls Pan Pan, which is reported to have been the original case here, the ATC controller on duty should prick up his ears, which didn't happen until the crew upgraded to Mayday.
The whole point of these phrases Mayday, Pan (and earlier Securite) is that they are international - regardless of poor English.
A couple of weeks ago we read of a Pan call by an English speaking crew over Madrid not being understood. Now we have a Pan call by a non English crew not being understood in an English environment.
Maybe it is time to review these procedures and make sure we are all familiar with them.
FC.