Most of Tolkien's writings on his invented languages will never be published as they are very technical. However, for a long time now a group has been allowed access to these materials by the Estate. This group's work is published in several different journals.
In one of them, Vinyar Tengwar, was published several Catholic prayers. Here is a sample .pdf (http://www.elvish.org/VT/VT43sample.pdf) that has the Our Father, Hail Mary, and Glory Be.
How interesting. :)