Hello all,

I recently came across this song on youtube, purportedly written before the schism between the Orthodox and Catholic Churches. However, when I asked some of my friends who spoke Latin for help in translating, they told me it does not sound Latin but is rather Gaelic. I am hoping that this song is able to be transcribed and translated so that in case this song is a particularly Irish version of a well known Latin chant, I may be able to contact the original poster on youtube so that they can make it easier to find. thank you for your understanding
https://www.youtube.com/watch?v=PD9iX4HZF9Y

I don't understand it, although I sometimes think I hear some Irish sounding words like "Íosa". But then if it's Middle Irish I wouldn't expect to understand it. And I don't know Latin either.
But there are more qualified people on this site.