Welsh symbols

You probably want to change the Keyboard Input Menu settings.

Open the System Preferences Application (you can do this from the Apple Menu or from the Dock). Now click on the International Preference Pane in the top row. Now click on the "Input Menu" tab.

Now scroll right to the bottom of the list of choices. "Welsh" should be right there. Click on the check button to turn it on. While you are still there make sure the check button for "Show Input Menu in Menu Bar" at the bottom is checked.

Now go to the Menu Bar at the top of your Desktop where the Keyboard Input icon should be displayed (it is probably showing the American Flag). Click on it and scroll down to where the Welsh Flag is showing. Click on it and now your Welsh characters should start working with your keyboard.

Griff

You can also make the ŵ and ŷ from the US Extended Keyboard layout, via Option + 6, then w or y.

If by chance you are using WordX, you can't input these characters, because that app (along with Appleworks) can't do the required Unicode. Just about any other app should work fine, including Word2004, TextEdit, Nisus Writer Express, NeoOffice, OpenOffice, Abiword, Pages, TextWranger, etc.