Here are the Welsh words to "Y Deryn Du" by Rn:

Y deryn du a'i blufyn sidan, A'i big aur, a'i dafod arian
A ei di drosta'i i Gydweli, I sbio hynt y ferch rwy'n garu.

A dacw'r ty, a dacw'r sgubor, A dacw glwyd yr ardd yn agor
A dacw'r goeden fawr yn tyfu, O dan ei bn rwy' am fy nghladdu.

Un, dau, tri pheth sy'n anodd i mi, Yw rhifo'r sr pan fo hi'n rhewi
A dodi'm llaw i dwtshio'r lleuad, A deall meddwl f'annwyl gariad.

Llawn iawn yw'r wy o wyn a melyn, Llawn iawn yw'r mr o swnd a chregyn.
Llawn iawn yw'r coed o ddail a blode, Llawn iawn o gariad ydw inne.

And the English translation:

Blackbird on silken wing,
Golden beak, silver tongued,
Fly from me to Kidwelly
To see how fares the girl I love.

There's the house, there the barn,
There's the open garden gate,
Over there the great tree growing
'Neath its shade may I be buried.

One, two, three things are difficult for me -
Counting the stars on a frosty night,
Reaching up to touch the moon,
Knowing the heart of my dearest love.

So full the sea of sand and shells,
So full is an egg of white and yellow,
So full the woods of leaves and flowers,
So full of love am I.