There is an ongoing confusion about the differences in the texts for the Propers as found in the Missale Romanum (that is, the Sacramentary) and the Graduale Romanum (or the Gregorian Missal produced in English-Latin from Solesmes). They are not identical and choirs learning the Propers often bump into the problem, and they don't often find an answer.
Let's say a schola works hard for a week on the communion chant. The pastor approaches the group with the observation that it is not the same one as found in the Sacramentary. What's up?
Well, I probably shouldn't do this but I'm going to anyway: the entire problem is resolved in an article coming out in the Winter issue of Sacred Music.
The article is by Christoph Tietze of the Cathedral of Saint Mary of the Assumption in San Francisco. He examines the history of where these Missale texts come from and demonstrates, beyond any doubt, the following: the Missale texts are for the recited Mass, whereas the Graduale texts are for the sung Mass. Missale texts were for functional purposes, where Graduale texts correspond with the beautiful tradition of liturgical music.
Simple right? Well, I didn't know that. Neither, apparently, did the Bishops Committee on the Liturgy, which introduced confusion in a translation of the IGMR. In fact, the final text is strangely ambiguous: "In the dioceses of the United States of America there are four options for the Entrance Chant: (1) the antiphon from the Roman Missal or the Psalm from the Roman Gradual as set to music there or in another musical setting..." (48). The Latin, however, is clear: "Si ad introitum non habetur cantus, antiphona in Missali proposita recitatur...."
I'm very excited about this piece that will have an impact on people immediately in their parishes. Finally, I say, finally!