I had no idea what an Archdruid was, here's what Wikipedia says:
"The Archdruid (Welsh: Archdderwydd) is the title used by the presiding official of the Gorsedd. The Archdruid presides over the most important ceremonies at the National Eisteddfod of Wales including the Crowning of the Bard, The Award of the Prose Medal and Chairing of the Bard."
For two years on this site there have been no dictation exercises, and maybe I was getting complacent. Now they are all over the place, and on the most unusual, unexpected things. Is it really necessary for me to hear and be able to spell Archdderwydd? And since I never hear Welsh being spoken by people, how do I know the metallic voice is anything like it?
The TTS voice is reasonably good. The various combinations of letters in Archdderwydd are quite common in Welsh.
Even if you do not have the chance to meet up with Welsh speakers very often, you can listen to Welsh at any time on British television and radio and on the internet. The television programmes etc are often available with Welsh sub-titles so that you can match the spoken and written forms.