no, they (when they sing,because that its very strange in most families) they sing spanish versions of the songs or religious songs too.
What i had seen lately is that parents buy a cd of Christmas songs for their small children to listen to. both, english or spanish versions.at home when i was very small we had a vinyl record XD i must have listened to it 2 or 3 times max, lol.sometimes adults at parties listen to classics in English(more like special versions by famous singer,generally modern versions)
on what i find most bizarre it is that instead of eating fruits and fresh things(itīs summer here) we eat chocolate and those stuff XD just like you guys. well, there is no eggjuice (canīt remember the name something endindg in och or nogg?)but people still loves eating chocolate and peanuts even at 43 Cš, jaja chocolate is very popular. some eat rosted chicken with potatoes as a dinner, other (well it is argentina after all) roasted red meat "asado".and if you are lucky ice cream/something cold as dessert, jaja. but every family is varied,i talk form what i have seen so far. for example, my family does not dress up at all.Others really do.
Everything Christmas-time is so regulated and traditional here, but it all hinges on things being... well... cold. It's rather odd to imagine people just doing their own thing instead of following all the... rules, I guess would be the word.