We are very fortunate in the English speaking world to have such a rich collection of Christmas carols - all the more reason to curse the ubiquitous noise pollution of Noddy Holder's "So heer id izz merry crissmuss..."
As a student in Rome, I was surprised to find out that there are not many Christmas carols in Italian that are popularly sung. In fact, the only one that seems to be sung ever is "Tu scendi dalle stelle". Nevertheless, it is by St Alphonsus Liguori and is quite charming.
I knew that it would be on YouTube but it did take a while to find a halfway decent version that did not mess about with it. Here is a version from the Portale Cattolico Italiano:
Words and translation here. H/T to Orbis Catholicus for reminding me of this carol.
(Now what I would really love to find would be a recording of "Inni e canti sciolgiamo fedeli.", a hymn to the Blessed Sacrament that Don Augusto Cecchi used to have at San Lorenzo. It is one of the most beautiful devotional hymns I have ever heard.)