Thanks for the link; there is a recording of the song in Irish, and also a recording of Kathleen MacInnes translation into Scottish Gaelic.

Title Teanga Bhinn Ár Máthar (Our sweet mother-tongue)

my quick translation of the first verse (the rest of the song continues very much in the same vein)

Listen, I hear in every quarter a soft beautiful sound
like the sound of a harp or the murmuring of the fairies
Listen, she is getting louder (rising and getting stronger)
Coming towards us on the wind
Wait, what is this around us, rustling and making music.
Is my mind confused or is this voice a vision/a dream?
It is not, it is not, friends, this voice all around us,
It is our sweet mother tongue awakening in Mayo


there is a reference in verse 2 to "The sweet language of St Patrick" [sic - Welsh? !]

the first verse in Gàidhlig
I am surprised at the use of "Cluinneam" for "I hear", as that tense has been lost in Scottish Gaelic and people usually say "Tha mi a' cluinntinn", "I am hearing"

Cluinneam anns gach ceàrnaidh fuaim bhog aoibhinn àlainn
Mar cheòl cho binn ri clàrsach neo crònan ceòl na sìth
Tha ise ag èiridh àirde le neart ' dol suas dhan àrda
Tha fuaim ag èirigh làidir ‘tighinn thugainn air a' ghaoith

Ciod e m'ar timcheall a' ceòltaireachd 's a' brìodal
Bheil mearbhall ' tighinn air m'inntinn neo 'n e aisling às a' ghlòr
Chan e, chan e, a chàirdean, tha 'n guth seo anns gach ceàrnaidh
Le teanga binn ar màthar a chùm dar reulta beò.