The English language lyrics given are close enough in meaning to the Irish.

My literal translation of lyrics submitted by Jim Dixon is (so far)

Oh, young Bríege O' Mally
You have left my heart broken
You've sent the pangs of death through the centre of my heart
Hundreds of men are in love with your quiet modest face
You are surely the most beautiful woman in Oriel.

There is nothing more beautiful
than the moon shining on the sea
or the white blossom growing on the blackthorn
My love is as brightly beautiful as that
[her] little honeyed mouth has never done wrong

I spend my Sundays sorrowful, my hat in my fist, sighing heavily
Looking at the road my love does walk
Now she is married to another, oh my grief, isn't it a shame

[I think "feall" implies he has been deceived - whether by Bríd or by her lover]
[often "agus gan i bheith liom" - "and her not with me" is sung rather than "is mo h-och nach í 'n fheall" ]

Aren't I the one who is cut down by this marriage
who will not sleep a single night but will be sighing/sobbing heavily
that I won't leave this world without me and my sweetheart
stretched on the same bed with my arm around her

I'm a nice young lad who aims to get married
but I won't live long if I don't gain my dear
my love [lit. pulse] and my treasure,
make ready and meet me next Sunday at the road
to Drumsleeve [droim sliabh - ridge of the mountain]