I just called the UAL nonrev line and was put on hold. There was this guy giving tips in the background with a very strong Spanish accent I couldn't understand half of his recommendations. Times are changing if they actually put people with accents on lines where it's critical that the person is understood. As far as flying I've never had any problems with the guys that I've flown with including one who had a strong Spanish accent. But then again, if those Air China/China Eastern guys can manage to talk their way from China all the way to the States, how hard can aviation communications be right?