Lilliana Skye
Maybe the change in language occured between when the whole princess fiasco happened and when Vulcagni and Phrigustus were accepted into the pantheon by mortals. That would have given some time for the language to alter as the story of the cities destruction and the princesses death spread. (I don't see a time frame in scripture, so this could be totally wrong and the prophet could have appeared a few hours after they were made into gods) I'll have to read the scriptures again, but if I'm not mistaken, Pejout and <insert name of Phrigustus here> did wonder the land for a long while..long enough to become more like their elements, I don't know.
Or the story could have arisen from a need to explain the appearance of the newd gods, sort of rewriting history to accomodate them.