One of the big differences between Eastern Orthodox Churches and Roman Catholic or Protestant churches is how music is used in the services. With Eastern Orthodoxy, a large percentage of the Liturgy (and most other services) is sung, but of that, much of what is sung is in response to what the priest is saying or praying. I suppose it’s a little like the stereotypical idea of one of these big, urban churches, with the pastor up front saying, “Can I get an amen?” or shouting “Hallelujah!” and having the choir and congregation respond back.
However, with the Eastern Orthodox Churches, I’ve never seen one that has had that type of energy, and the responses involve a lot of “Lord, have mercy”, “to Thee, O Lord”, and “Amen” (though not the gospel type of “Amen!”) Each service also has other parts, some of which are pretty constant throughout the year, but others which will change depending on the service and the season. I believe the Lord’s Prayer and the Creed are in every Liturgy service, but that there’s some variation throughout the year of most other parts.
The parts that change every week are called Troparions and Kontakions, and they commemorate any celebrations (feast days) or people for that day. For Nativity (Christmas), the Troparion text in English is something like this (translations vary):
Thy Nativity, O Christ our God, hath shined the light of knowledge upon the world; for thereby they that worshipped the stars were instructed by a star to worship Thee, the Sun of Righteousness, and to know Thee, the Dayspring from on high. O Lord, glory be to Thee
People who have been Orthodox for awhile just know that this is the piece that goes into that place of the Liturgy. It’s quite different than picking hymns out of the hymnal for the choir and congregation to sing.
This is one of the reasons that the “kolady” aren’t generally sung in church – liturgically, they really don’t fit. There’s really only one place where they can be “snuck” in, and that’s when the priest is in the altar before he comes out with Communion, but although sometimes liturgical songs are sung here, they don’t necessarily have to be liturgical, because this is an interlude to give the people something to listen to while they can’t see the priest.
Once the priest comes out with Communion, though, it’s back to the regular liturgical programming until the end of Divine Liturgy.
What happens in a lot of parishes is that since Christmas services tend to be more full, and it’s cold outside, there are a lot of people who mill around a bit before leaving the church proper. Many choirs take this time to go through a lot of the old carols. For some people, hearing them is a huge part of Christmas, and not hearing them would be hugely disappointing. The days of families living within walking distance of the church and visiting with each other, and singing the old carols amongst friends has long since passed.
Yet, it’s hard, too, for many people who don’t have the ethnic background to really feel like it’s Christmas without singing some of the famous Western carols in church. In my 20 years in Orthodoxy, I have been part of parishes who sing pretty much only “western” carols, and I have been to parishes where the attitude was that the western carols get played all the time everywhere else, so the “ethnic” carols had better get sung every chance available. It’s very much going to depend on the church.
That being said, whatever is the case, it’s just good to do everything in a spirit of charity, especially at Christmas. I don’t know of any western religious carol that anyone has called out as being theologically unsound. That’s not a guarantee that your favorite song will get sung though. As much as the “ethnic” carols don’t remind me of Christmas with my family growing up, I have learned a number of them, knowing that for some people – and this generation is quickly dying off – hearing them is precious, especially when they don’t have YouTube or Spotify or whatever. Oh, gosh, but how things start getting crazy when your choir director has the choir sing “Silent Night” in English and the “original language”. What language would that be? I’m not even sure, but it’s not German, and it’s not Russian!