Hmm... I just thought about a related problem for Superman and Clark: A sociolinguist could pin him down by the way he speaks: Not only should his accent in theory point to Kansas, but also his word choices -- whether he says "soda" or "pop," for example. The more he speaks in public, the more likely he is to used regional choices of words. If you eliminate the Metropolis-area vocabulary choices, the other regionalisms are likely to point mostly to Kansas. (I wrote "mostly" because he may well have picked up some regionalisms from his various travels.)
