A load of yobs from PenrithPedanticus writes: It has to be pointed out that the "th" in "with" is voiced, making strict rhyming impossible. Using Welsh is not possible because the stress would be on the wrong syllable. The only solution to this impasse is to assume marked Caledonian chararcteristics on the part of Superman
(KagShu) I'd say the difference is like the difference between the th's in thing and there, this, that etc. I don't think there's any difference between American and British English on this point.
[Superman] You can hope, and you can stack the deck with a difficult rhyme in the first line, but in the end you get no more say in the finished product than if you'd played a move that offered wide-open possibilities to everyone else.