(Apologies if this has already been discussed somewhere here and I missed it.)
To those who are generally disinclined to seek edifying material in the pages of NPM's January 2015 Pastoral Music, I joyfully recommend that you not pass up this excellent article by our own Dr. Paul F. Ford.

It is often (perhaps "usually") the case that our discussion of chant is dry and technical. This aspect is important, because in the end it is often a very fine science that goes into sublime beauty. But it is worthless if it is not prayer. Dr. Ford shows us how the chant originated as prayer, and how the process of prayer went even into the melodic motives, using the Gregorian introit Laetetur cor as an example. And what an excellent example it is, inviting us to put our own hearts into what we are singing.

I also appreciated the color-coding of musical motives. This is something I occasionally do with my choir as well.

(Be aware that your issue may have pagination issues; mine was stapled incorrectly, but just be persistent in finding the proper sequence. The article begins on p 29, and skips 30-31, and continues on 32-34.)