BYB commented: So far, no takers on Adeste Fideles. Those are, of course, the Latin words to "O Come All Ye Faithful", which everyone I know assumes to be a medieval hymn, since it was originally written in Latin.
I think most of us old Latin hammerers understood that.

Nowadays when a group of people gather -- be it at The Pops for Christmas or anywhere else -- you can generally tell the old-time RCs from the post-John XXIII RCs and Protestants by whether the singer uses the Latin or the English lyric. Or so I've found. Sine I am generally bad at Latin I use Adeste to bulk up my credentials and sing it in Latin!
Do they even teach the Latin lyrics outside of formal choral settings?
wow