What language is the song Teir Abhaile Riu by Celtic Woman in?

"Teir Abhaile Riu" (pronounced "Tare Ava-lee Ree-oo") is sung in Irish Gaelic.

The song is a traditional Irish lullaby with lyrics that translate to "Go Home to Him". The song is a beautiful example of Irish folk music, with a haunting melody and evocative lyrics.