In the past, Welsh babies were usually given names from the Welsh language. For boys this meant names like Llewellyn, Carey, Bevan, Rhys, Tristan, and Gareth. Nowadays, boys often have names that come from the English language like Oliver, Jack, Ethan, Harry, and Charlie. The same thing goes for girls names. In history, girls had names like Gladys, Eira, Morwen, Gwenyth, and Briallen. Common names now are Lily, Ruby, Rose, Ella, Mia, and Olivia.
In recent years the Welsh tend to name their babies the same as the English do. Sometimes families will give their children both an English language name (like David) and its Welsh equivalent (in this case, Dydd.) When they grow up some people use exclusively their English name of their Welsh name. Other people use their Welsh name sometimes (such as when speaking Welsh or with their family) and their English name at others (like in the workplace).
Online Welsh lessons for kids: dinolingo.com