The Parenting Passageway has a good post on the December 13 festival of Saint Lucy/Santa Lucia called Santa Lucia Day in the Waldorf Home. In the post is an embedded link to the Swedish Santa Lucia song as well as a link to lyrics translated by Mama Lisa's World.
In my daughter's school, the song has been simplified to these few lines:
Now in the darkest night
Enter with candlelight
Santa Lucia! Santa Lucia!
For this blog, I sang the song twice on video: