Lyrics copied from http://home.earthlink.net/~myrrhis/donalog.htm
This version is similar to the one posted by skallagrigg above, but it is missing skallagrigg's last verse, and it has 3 verses skallagrigg's version doesn't have. There are some other differences; I have marked them with boldface.
If you should go across the water,
Take me with you to be your partner.
At fair or market you'll be well looked after,
And you will sleep with the Greek King's daughter.
I saw you first on a Sunday evening
About the Easter when I was kneeling.
'Twas about Christ's passion the priest was reading,
But my eyes were on you, and my sad heart pleading.
Oh Donal Og, you'll not find me lazy,
Not like some highborn, expensive lady,
I'll milk your cow and I'll nurse your baby,
And if you're set on, I'll defend you bravely.
You said you'd meet me, but you were lying.
Down at the sheepfold, as day was dying,
I whistled first, then I started calling,
But all I heard was a young sheep bawling.
My mother said we should not be meeting,
That I should pass you and not give you greeting.
She should have told me all that before.
When the house is robbed, why lock the door?
You took what's before and what's behind me,
The east and west, when you wouldn't mind me.
Sun, moon and stars from my sky you've taken,
And God as well, or I'm much mistaken.
It was late last night, the duck called your name.
Down in the marshes, the snipe did the same.
You are the lonely bird in the tree.
May you stay lonely 'til you come to me.