How do you pronounce ceulan in Welsh?

"Ceulan" is not a word in Welsh. It's likely a misspelling or a name that's not part of the standard Welsh vocabulary.

Could you please clarify what you mean by "ceulan"?

* Is it a specific word you heard or read? If so, could you provide more context?

* Is it a name? If so, is there any other information about the name, like its origin?

With more information, I can help you figure out how to pronounce it.