The song we all know as the "Ukrainian Bell Carol" was originally a New Year song performed by carolers going door to door, wishing prosperity in the coming year.
Here is a performance of the original version with English translation. FYI, it never mentions bells at all. Those words were written later by Peter Wilhousky when he repurposed the song.
Mykola Leontovych - Щедрик (English Translation - Shchedryk)
https://www.youtube.com/watch?v=fXcFcSmqOGg
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^ Once you know the original meaning, you understand that the repeated 4-note motif represents the bird singing.
But what's with the emphasis on dark eyebrows?