A friend and I were just talking about chanting propers and we sort of went through the basic issues that you face once you enter phase two of chanting, once you have developed a sense of the genre and the line of music. What are the issues that you have to work through in order that you can get the point of reading through the Graduale and producing any chant with consistent beauty?
So we hammered out a list:
1) Legato phrasing. This is a major issue for singers. Somehow it is easier for instrumentalists. Brass players know how to make a legato line because it is simply a matter of doing something mechanically different. But singers just naturally tend to bump from note to note, especially when we are not fully accustomed to the musical language. So at first, before you get into the habit, you have to constantly think: "Sing legato, sing legato." This goes on for months until it becomes habitual. You have to constantly remind yourself and singers.
2) Phrasing in general. When you sing you have to breath somewhere, and you have to stop and start. Where in the music do you do this? How can you come to understand the broader structure of the piece of music? The first impulse is to understand the words and subdivide the chant that way. That can work, but it is not the best route. The first step should be to understand where the arsis and thesis is, where the musical ebb and flow is going, when to repose and when to lean forward in the phrase. Once that is conquered, you can add texture by infusing the text with textual articulation and meaning. The second step is necessary but secondary to the music in terms of rehearsal.
3) Learning solfeg. Everyone has some primary musical language. It could be piano. It could be trumpet or flute or guitar. It is usually the first instrument we played in life, and we hang onto it forever. Through this instrument we come to understand the relationship between notes. So when most singers sing, they are mentally "playing" some instrument. The problem is that this only gets you so far in chant, because you are always in the translation stage. You need to make the musical language of chant your primary, workable, viable, speaking/singing language, and that language is none other than solfeg (Do, Re, Mi). You have to use this often to become fluent. It has taken me years, and I'm still not there. It's like learning French or Hebrew to the point of fluency. It is the biggest challenge that chant singers face. But there are tricks, such as the body motions for associating solfeg with spots on the human body (Do is stomach, Re is chest, Mi is chin, Fa is nose and note the short space on the half step).
These three issues are what make the difference between a competent group and a masterful group of singers. I probably should add vowels in this list but I'm not sure what to say about it other than to say that sung vowels are different from spoken vowels; in any case, good vowels is not a problem unique to chant, but the other issues of legato, phrasing, and solfeg are especially at issue in chant.
Finally, let me say that friendship is the most valuable thing you need in entering this stage. I just received an email from a friend who was puzzling about where to place the ictus in this weekend's offertory, and he was marveling over the salicus at the end. You have to have people you can talk to about these issues, since it is not likely that you can do so at a regular block party or something. We are all crazy, and need each other.