I think we probably are in agreement, sophocleese - but there are some pretty nasal accents in England, and the carols sound alright with them. I think people should always feel free to take a song such as a carol and sing itnwithin their own tradition - but need to show respect while they are doing, and recognise where change is needed, and where it's not.

I think Americans often aren't aware quite how widely accents still vary within short geographical areas in England. I once got lost in Birmingham and had to stop and ask the way half a dozen times. Each time it was a drastically different (though unmistakably Birmingham) accent. And pretty nasal at that.