[toyg]

Loads of Latin and Italian words were modified across the world, not unlike what happens today with English; it's perfectly possible that accountants trading predominantly in the New World or some other remote area could have come up with their own approximation for a word (milione) that is not from Classic Latin and is actually pretty recent (wikipedia says XIII to XIV century, whereas lira and soldo are much older and denario goes all the way back to Rome fighting Carthage).