Lyric discussion by tedsplitter 

This is about Mary, who was a woman with whom Billy had a brief intense relationship in the late 80s. They got engaged and it all went wrong and most of the songs on 'Workers Playtime', the album from which this is taken, are about her. I hear she was into "spiritual" stuff, which is where the 'mumbling in latin' comes from and the 'spell' of the title.
However, I've been wrong before and I promise I'll be wrong again...

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