reviving this song thread for Easter; really I should have done this on Friday.
What a distressing image of a woman seeing her child suffer! But still a beautiful lament.

best known recordings of this Caoineadh are by men
Seosamh O hEanaí
Cóír Chúil Aodh

though you could argue that it is a woman's song
Nóirín Ní Riain

(links to youtube recordings; there are a few recordings by other artists on the site as well. And Peter Laban provided two links to recordings earlier on in this discussion. I haven't checked whether the links are still working.)
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re Muire/Mhuire, as noted by Keberoxu; Mh has a w sound. The alteration of the name Muire happens because it is preceded by a number, Trí (three). Trí itself is lenited because of the genitive, this is the keen "of the" (na d)Marys.