This question came via e-mail:
I have seen a number of patterns of spoken congregational response in Masses in the Extraordinary Form. Occasionally you get something like the old "Dialogue Mass", a low Mass where the congregation joins the server for many of the responses. But not long ago at a low EF Mass I was admonished by the lady next to me in the pew when I said "et cum spiritu tuo" after the priest’s "Dominus vobiscum" — it was an almost unconscious response on my part. She tapped me on the shoulder, scowled and hissed "shh". I hadn’t spoken at all loudly, but clearly she felt it was wrong to respond. Seems to me that it’s the priest’s role to decide whether the congregation responds, and to signal that somehow to the congregation.
So: when should the congregation respond vocally in a low EF Mass, or a Missa Cantata, or a High Mass? How can priests provide guidance on this?
Ah, yes. The Hissing Lady. All too common in some places where the TLM is celebrated I’m afraid.
There is no hard and fast rule about vocal responses. I think you have to go with the flow.
That said, various Popes before the Council encouraged congregational responses, the so-called "dialogue Mass".
On 3 Sept 1958 (anniversary is coming!) an extremely important document, De musica sacra, was issued by the Sacred Congregation of Rites. This document established rules for the outward participation of the congregation in three different levels for the Missa cantata and the Missa solemnis.
In the first, the people would also sing the liturgical responses. In the second, they would also sing the Ordinary. In the third, they would also sing the Proper.
De musica sacra also established rules for Low Mass in four levels of outward participation. First, answering aloud the short responses. Second, also saying all the responses the server would say as well as the Domine non sum dignus. Third, also reciting with the priest celebrant his parts of the Ordinary, the Gloria, Creed, Sanctus, Our Father, etc. Fourth, also saying the Propers, the Introit, Gradual, Offertory, Communion antiphon.
In my travels, I have seen various levels of participation. In some places the congregation is pretty silent, leaving everything to the servers or choir. In others, the Hissing Ladies are vigilant. In yet others, people speak and sing without censorship. Much will depend on what the priest wants and promotes.
But yes, congregational responses are permitted and, in many cases, a good idea.
Personally, I prefer responses from the congregation and have no problem at all with them saying the parts pertaining to the server, and even prayers like the Gloria and Creed.
What I do not like are the Hissing Ladies of both sexes.
But I think you have to go with the flow.