Well, thank you all three! 'Twarn't I misspelt the Welsh! (My Welsh is limited pretty much to distinguishing Cymru from Cymro from Cymraeg; and recognising "Gwasg Prifysgol Cymru", for that matter, now that I think about it.) The misspelt Welsh was copied directly, electronically from this page (which is part of the same site Graham sends me to for the other text). If there are misspellings perhaps someone who knows what they're talking about ought to notify that site's folk.

My house mouse died last night, which may delay my further response, but I did want to thank you. Even Grab; I agree with sian that Clementine's a bit of a stretch. (Though it's easier to imagine than, say, singing Clementine to the Internationale...)

Liland