There are some Macaronic songs in Welsh/English, sometimes every other line and a few with words interspersed throughout.

A ai di deryn du (will you go, blackbird,)
to my dearest love
O gais fy nghangen gu (o search for my lovely one)
for I'm so deep in love.

Being an example of the first, and Cân Merthyr (Merthyr's Song) combining both in one:

Ye lads all through the country
Gwrnadewch ar hyn o stori. (Listen to this story)
You better go dros ben y graig (Over the rock i.e. jump off a cliff)
Than go with gwraig i'r gwely. (wife to bed)

sian