No, no, no the Our Father chant is
standard from parish to parish, which means that it IS written down somewhere. We’ve heard it in other parishes besides our own.
But no one ever tells us where it is written down.
If it was done week after week, every week, we would probably eventually learn it. But that’s the problem–it’s done every once in a while, so we don’t ever have the chance to learn it.
Although actually that’s just fine with us. Sorry to let you down, but both my husband and I really don’t “get” chant prayers. It seems incredibly strange–I mean that in complete seriousness–
incredibly strange–to us to “sing” our prayers in a more or less monotone chant. Singing a melody is OK for praying, but simply elongating a speaking voice–it just doesn’t make sense to us.

It doesn’t sound “reverent” or “mysterious” or “beautiful” to us–it just sounds weird. We’ve been Catholic now for ten years, and we still prefer just spoken prayers, thank you very much.
Perhaps it would help you and others to understand us by flipping things around. Many Catholics think it is incredibly strange (and downright irreverent) to have rock music with a full rock band in a worship service. We don’t find that strange at all. It’s what we were used to, and we still feel that it is grand and inspiring and very appropriate in the presence of God (not the True Presence, but present in the sense that God is omnipresent). Same for Gospel music–IMO, this music alone is The Music that best suits worship of God, because you don’t really ever hear it in any other setting other than “church.” Chant and polyphony are performed in concert halls all the time, but not so much with true “Gospel” music (even Southern Gospel is performed mainly in churches).
So I hope that helps you to put yourself in our shoes and see how we view chant.
Back before we converted to Catholicism, I used to say to my husband, “Catholics have more faith than any Christians, because the Mass is so strange.” I still think that. Other than Jesus in the Blessed Sacrament, there is very little in most Masses, either OF or EF (and probably Latin OF–that one I’ve never heard) that would attract or hold anyone from week to week for a lifetime. It’s purely an exercise in complete and total faith.