Translation:Wales and Brittany share a national anthem.
Where can one get the words in Welsh? I love to hear it sung before international rugby matches. The Welsh sing it with such fervour!
There's a wikipedia entry, there are various youtube videos and also a really good app called 'Dragon Songs' which teaches how to sing it phonetically from English.
Here are some links to the three national anthems that are the same:
Cymru/Wales: Video https://www.youtube.com/watch?v=yEOxEHS6et4 : Lyrics https://en.wikipedia.org/wiki/Hen_Wlad_Fy_Nhadau
Llydaw/Brittany: Video https://www.youtube.com/watch?v=8J2CIhA1mwE : Lyrics https://en.wikipedia.org/wiki/Bro_Gozh_ma_Zado%C3%B9
Cernyw/Cornwall: Video https://www.youtube.com/watch?v=ojdZaPeJjAo : Lyrics https://en.wikipedia.org/wiki/Bro_Goth_agan_Tasow.
Interesting to note is that the Breton and Cornish names to the song are closer than the Welsh because they are both southern brythonic languages whereas Welsh is northern brythonic. (Also "Bro" is a Welsh word that also means country except we mostly use "Gwlad" now).