Ah! That's because none of those is the "real" version. They are all translations of the original. The original is in the Gaelic. All of the others are interpretations, since you can't really put Gaelic concepts directly into English in a literal form and still be singable.

Look at those old threads above, since we had a great discussion on that. I think it was Noreen who was looking for a "true" English version.