The spelling of the name "Gwillyn" may seem confusing at first, but it adheres to Welsh phonetic rules. This name is pronounced as [ˈɡwɪliːn], with a "g" sound like the "g" in "go", followed by a "w" sound, and then a long "i" sound. The double "l" represents a Welsh sound that is similar to the "th" in "breathe". Finally, the "yn" at the end of the name is pronounced as a short "in" sound, as in "pin". Despite its unconventional spelling, "Gwillyn" is a popular name in Wales.