He and his sister were talking about words. She said, “You know where spitting image comes from?”
“It was originally spirit in image. It was a religious reference. Somehow it got twisted into spitting image. I think it’s probably from someone’s accent confusing people, so they thought someone was saying spitting image instead of spirit image.
He later searched for origins, and spirit in image wasn’t mentioned. Shame, though, it sounded like a good story.