First, at
this page that chapter heading is written this way: “On not celebrating the Mass every where in the vulgar tongue.” There is a big difference between “Mass should not be celebrated in the vulgar tongue” and “Mass should not be celebrated in the vulgar tongue everywhere.” The latter leaves room for Mass to be celebrated in the vulgar tongue and helps show that this was a discipline, not a doctrine.
Second, I want to emphasize that distinction between discipline and doctrine. Just because a document is headed by the word “doctrine” does not mean it does not refer to disciplines too. In this case, the Council of Trent, if I’m reading it correctly, ruled that Mass should not be said
everywhere in the vulgar tongues. So it wasn’t. But I do think it allowed Mass to be said in some places in the vulgar tongue – like Greece, where I believe Greek Catholics had always said, and continued to say Mass, in Greek.
So there is your “other doctrine” that says that Mass can be celebrated in non-Latin languages, and it’s not a doctrine, it’s a discipline. I don’t think that would be the language’s fault. How would you answer the following argument?
Premise 1. Something can only cause irreverence at Mass if it is inherently inappropriate for Mass.
Premise 2. Non-Latin languages are not inherently inappropriate for Mass because they have been used in the Mass with the Church’s approval for centuries.
Conclusion. Therefore, non-Latin languages cannot cause irreverence at Mass.
Do you think that is a valid argument?