Goleuddydd
This name means bright day, also a Welsh name. It is pronounced Go-loo-theeth.
Goleuddydd is a variation of Goleudydd, which is made from the elements meaning "light" and "day." It is pronounced something like /gah LYE dith/ (the "th" being like the end of "with" as opposed to the beginning of "throw.") The middle syllable may be pronounced more like "UH'ee" depending on your accent.