MS 22-26

22. Depending on the established customs of peoples and on other circumstances, a choir may be made up of men and boys, of all men or all boys, of both men and women, and, where the situation really requires, even of all women.

Is this the first time that a document allowed women to take part in a choir? I know that the practice was frowned upon if not forbidden before the council . . .

23. According to the design of the particular church, the place for the choir is to be such that:

a. its status as a part of the community with a special function is clearly evident;

b. the performance of its liturgical ministry is facilitated; [20]

c. full, that is, sacramental, participation in the Mass remains convenient for each of the members.

When there are women members, the choir's place is to be outside the sanctuary.

From the above, I think you could make a case for the choir placed in the loft or in front. I'm not trying to make a case for the presence of the choir in front, just stating that MS doesn't seem to forbid it.

As to the last item, is there an assumption at play here that says that women will never be in the sanctuary?

24. In addition to musical training, choir members should receive instruction on the liturgy and on spirituality. Then the results of the proper fulfillment of their liturgical ministry will be the dignity of the liturgical service and an example for the faithful, as well as the spiritual benefit of the choir members themselves.

Exactly. I think that it is imperative that our choir members have a greater understanding of the liturgy than the average pew-sitter.

25. Diocesan, national, and international associations for sacred music, especially those approved and repeatedly endorsed by the Apostolic See, are to offer help for both the artistic and spiritual training of choirs.

I think this one if finally getting off the ground. NPM has been around for quite a while but it seems that the CMAA is finally growing and the advent of these chant colloquiums seems to indicate that more is on the way.

26. The priest, ministers, servers, choir members, and commentator are to sing or recite the parts assigned to them in a fully intelligible way, in order to make it easier and obvious for the congregation to respond when the rite requires. The priest and the ministers of every rank should join their own voices with those of the entire assembly in the parts belonging to the congregation. [21]

"Commentator"? What's a "commentator"?

The last sentence should be anonymously forwarded to every priest in the US :)

20. See Sacred Congregation of Rites, Instr. Inter Oecumenici, 26 Sept. 1964, no. 97.

21. See Sacred Congregation of Rites, Instr. Inter Oecumenici, 26 Sept. 1964, no. 48 b.