We have sung in many languages, and our children's choir regularly sings in swahili and other african languages, as well as hebrew and latin. The congregation doesn't usually complain, but it helps that the full translation is always put in the bulletin. We have hymns in the hymnal in a bunch of different languages, too, all phonetically notated. But as etaoin says, it doesn't really matter if it's sung correctly; it's the meaning that counts. As a choir we are much more picky about the pronunciation, but fortunately have "experts" for most. I love latin because it's a similar pronunciation to spanish, and therefore easy for me. But make me sing in french and you might hear a little grousing... ;0)

PS Here's one from our anthem this week that I had to look up: overdight (yes, that's English...)