Here are the lyrics as I have them. This version either omits verses or others have been added later. As best as I can guess, the chorus (roughly translated into English) is "I wish, I wish, I wish in vain. I wish I had my heart again and vainly think I'd not complain". I read also that "Is go dté tú mo mhúirnín slán" means "And may you go safely my darling".


I wish I were on yonder hill
'Tis there I'd sit and cry my fill
'Til every tear would turn a mill
Is go dté tú mo mhúirnín slán

Chorus:
Siúil, siúil, siúil a rún
Siúil go sochair agus siúil go ciúin
Siúil go doras agus éalaigh liom
Is go dté tú mo mhúirnín slán

I'll sell my rock, I'll sell my reel
I'll sell my only spinning wheel
To buy my love a sword of steel         
Is go dté tú mo mhúirnín slán

Chorus

I'll dye my petticoats, I'll dye them red
And 'round the world I'll beg my bread
Until my parents shall wish me dead         
Is go dté tú mo mhúirnín slán

But now my love has gone to France
To try his fortune to advance
If he e'er comes back, 'tis but a chance         
Is go dté tú mo mhúirnín slán