Well, I can't find a suitable English translation, but until I do -- or a suitable translation comes from someone better qualified than I -- here is a sort of abstract of the Breton verses.

I am a young man, literate, earning my own living, and I have something to tell you all before we turn in for the night: there is no rest, day or night, for him who has his heart set on one girlfriend.
I went courting, and the girl told me I should go away and study for a year or two. My studies were not yet over when she sent a letter warning me that her parents were going to marry her off. When I finally got there, it was too late. She told me, Don't make the mistake I made, get another girl, because I am married to another now.
In the last verse, the ancient Christian symbol of the pelican is evoked, with its bleeding bosom, to describe a heart broken open and poured out.

This is skimmed off of one of the YouTube comments.