I've read that the Breton form of Cinderella is Luduennig (from ludu, ash + -enn, singulative suffix + -ig, diminutive suffix).
I wonder what the corresponding Welsh form would be. Could something like lludwenig (lludw + -en + -ig) work?
Well, never mind. There are so many translations in other countries, as jazyk says, I thought there would be one in Welsh too.
Now I wonder how Cendrillon came to be translated into Breton in the first place...