Usually called Am Bothan a Bh'Aig Fionnghuala (Fionghuala's Bothy), the song in the DT is Scottish, not Irish, Gaelic, and came from Calum Johnston of Barra; the Scots spelling system is both more difficult and more logical than the (modernised) Irish.  The DT entry is labelled @Irish, which is a commonly-occuring mistake here where songs happen to have been recorded by popular Irish performers.

There is a longer set of lyrics in this discussion from a couple of years back, if you can cope with the complete lack of formatting:  Fionnghuala

George Seto has transcriptions and translation of Johnston's set (but with an additional verse) and of another, virtually the same but with a simpler chorus, Eilean nam Bothan, which I take to be the one later recorded by the Bothy Band, at his site:  Fionnghuala

There is a midi of the tune, made from a transcription of Johnston's singing given in the accompanying booklet to Music of the Western Isles (Tangent TNGM 110, 1971; now available on CD from Greentrax) at the Mudcat Midi Pages:  Mudcat Midi Pages:

Fionnghuala

I differ from many people here in that I think it wrong to attempt to sing songs in a language that one does not understand; learning a thing parrot-fashion from a "phonetic" transcription is the sort of thing opera singers do, but I believe that traditional music deserves more respect than that.  Other peoples' culture is not such a cheap thing that it can be so quickly and easily won; the thing to do is to attempt first to get at least a basic grasp of the language concerned, so that you have some idea what you're doing.

Malcolm