I missed set dancing tonight because I went to see a play by Eugene Ionesco, performed in Irish. I didn't understand it, but they do call this sort of drama "theatre of the absurd". At the interval, I asked Paddy and Tomás in the seats beside me about "Jingle Bells". We all remembered different lines, and this is how it comes together:

Bualadh bas, bualadh bas, bualadh bas go leir
Tá Daidí Nollag ag teacht anocht anuas an simleir.
Bualadh bas, bualadh bas, bualadh bas go leir
Tá Daidí Nollag ag teacht anocht anuas an simleir.

Tá Nollaig buailte linn;
Tá athas ins an aer.
Tá sneachta ar an talamh;
Tá rêaltaí ins an spêir.
Táimid ag dul ar gcodladh;
Tá ar stocaí reidh.
Tá Daidí Nollag ag teacht anocht anuas an simleir.

If you can improve on this version, please do. There's no word of a "one horse open sleigh": Christmas is coming. There's joy in the air, snow on the ground, stars in the sky. We're going to sleep; our stockings are ready. Father Christmas is coming down the chimney tonight.

As for the request for phonetics, if you don't know the language you really need someone to teach you the words -or failing that, a recording (Blackcat has the right idea). There are some pronunciation guides on the net; I don't know how good they are. The following URL was recommended on a previous thread: http://www.standingstones.com/gaelpron.html