If you will countenance another comment from SLF, I noticed that on LH planes, there is this list next to the phone receiver for cabin announcements, of which buttons to press for the recorded announcements in various languages. I'm not 100% sure whether it's actually used on all international flights, but this would seem to take care of at least the everyday security needs. Not the G&T of course and probably not an emergency, but that's another matter. Anyway, in an acute emergency, I guess most communication would be simple enough that even accented language skills should suffice.
As for on-ground service, jensdad, shall we amble over to the SLF forum maybe?
