some of the links posted in this thrad in 1999 don't work now.
So here is a set of lyrics from http://www.irishpage.com/songs/roisdubh.htm

the English translation here is credited to Pádraig Pearse and the Irish to Eoghan Rua(dh) Mac an Bhaird (http://www.ainm.ie/Bio.aspx?ID=1328 lived circa 1570-1630 bio. makes no reference to Róisín Dubh). Pearse's English rendition is a fair translation of the Irish lyrics given below:

Róisín Dubh

A Róisín ná bíodh brón ort fár éirigh dhuit-
tá na bráithre ag dul ar sáile is iad ag triall ar muir,
tiocfaigh do phardún óa bPápa is ón Róimh anoir
is ní spáráilfear fíon Spáinneach ar mo Róisín Dubh.

Is fada an réim a lig mé léi ó inné do dtí inniu,
trasna sléibhte go ndeachas léi is mo sheólta ar muir;
An éirne scoithe sí de léim í cé gur mór é a sruth;
is mar cheól téad ar gach taobh di a bhíonn mo Róisín Dubh.

Mharaigh tú mé, a bhradóg, is nár ba fearrde dhuit,
's go bhfuil m'anam istigh i ngean ort is ní inné ná inniu.
D'fhág tú lag anbhann mé i ngné is i gcruth;
ná feall orm is mé i gnean ort, a Róisín Dubh.

Shiúlfainn féin an drúcht leat is fásaigh goirt
mar shúil go bhfaighinn rún uait nó páirt ded thoil;
a chraoibhín chumhra, gheallais damhsa go raibh grá agat dom,
is gurb í plúrscoth na Mumhan í mo Róisín Dubh.

Dá mbeadh seisreach agam threabhfainn in aghaidh na gcnoc
is dhéanfainn soiscéal i lár an Aifrinn do mo Róisín Dubh;
bhéarainn póg don chailín óg a bhéarfadh a hóighe dhom
is dhéanfainn cleas an leasa le mo Róisín Dubh.

Beidh an Éirne 'na tuilte tréana is réabfar cnoic,
beidh an fharraige 'na tonnta dearga is an spéir 'na fuil,
beidh gach gleann sléibhe ar fud Eireann is móinte ar crith,
lá éigin sula n-éagfaidh mo Róisín Dubh.

TRANSLATION

Little Rose, be not sad for all that hath behapped thee:
The friars are coming across the sea, they march on the main.
From the Pope shall come thy pardon, and from Rome, from the East-
And stint not Spanish wine to my Little Dark Rose.

Long the journey that I made with her from yesterday till today,
Over mountains did I go with her, under the sails upon the sea,
The Erne I passed by leaping, though wide the flood,
And there was string music on each side of me and my Little Dark Rose!

Had I a yoke of horses I would plough against the hills,
In middle-Mass I'd make a gospel of my Little Dark Rose,
I'd give a kiss to the young girl that would give her mouth to me,
And behind the liss would lie embracing my Little Dark Rose!

Thou hast slain me, O my bride*, and may it serve thee no whit,
For the soul within me loveth thee, not since yesterday nor today,
Thou has left me weak and broken in mien and in shape,
Betray me not who love thee, my Little Dark Rose!
[*dictionary definition of bradóg = a roguish woman]

I would walk the dew with thee and the meadowy wastes,
In hope of getting love from thee, or part of my will,
Frangrant branch, thou didst promise me that thou hadst for me love-
And sure the flower of all Munster is Little Dark Rose!