In Devin Garrity, ed. "The Mentor Book of Irish Poetry", 1965, the poem is titled simply "What Tomas Said in a Pub". The poem is not attributed to anyone else apart from James Stephens. I checked some poems which I knew to be translations from the Irish, such as "Pearl of the White Breast" (George Petrie translation of 18th century song) and "The Old Woman of Beare" (Frank O'Connor translation from 8th century Irish) - those were attributed, but the Stephens' poem was not. It was from a Liam Clancy album cover that I originally got the information that "What Tomás an Buile Said in a Pub" was a translation. still seeking further details...