It might not seem so, but the spelling of Irish was actually considerably simplified in the middle of the last (20th) century by the introduction of the Caighdeán Oifigiúl do litriú na Gaeilge. Before that it was much more complex.

The title translates as the Official Standard for spelling of Irish (Gaelic). It is pronounced (sort of) like Ky-John If-ig-ool de lit-roo nah Gay-leg-eh.

If I am not mistaken this work was carried out by the early Irish Government rather than the Christian Brothers although the CBs probably had a hand in it somewhere. My experience of a CB School was that there were many who loved the Irish language even more so than Latin. We had one particular Brother who used to throw you out of the classroom for speaking English - even during the English Lesson.