In 17th century Yorkshire, after the morning service on Christmas Day, people used to take hands and dance through the church shouting “Yule! Yule! Yule!”
I'll bet the vicar just loved that.
Crying Yule as a refrain to seasonal songs, chants, and dances is an old custom in the English-speaking world (as it still is in Scandinavia) with parallels in a number of non-Germanic cultures. To take just one example, a standard refrain in Latvian Midwinter carols is Kalado, Kalado; Kalado means “Christmas,” but it's yet another descendant of the wide-spread and influential Latin calendae, like Provençal Calena and Russian Kolyadá. The calends of January have much to answer for in the course of cultural (and linguistic) history.