Cerdd Dant - This is a traditional form of Welsh singing where the singer sings a different, but complementary, tune to the one played by the harp. The harp starts first, then the singer joins in. Here is an example of Cerdd Dant from the 2013 National Eisteddfod https://www.youtube.com/watch?v=-pk0ln368Go4
The harp tune for you to sing to is called ‘Morfa’r Frenhines’ and is given below. You may use any Welsh song you like to go with the tune.