>I reject Trent as a heretical council so I couldn't care less,
I wouldn't expect a Protestant to accept Church councils, but I do wonder at what point do the protestants think they were valid? When did they "split"? Does your belief say that the Church sprang up with Martin Luther or King Henry, and didn't exist until then? Or are you a Baptist that will tell me that the founding of your religion with John Smyth really began before Christ?
>but I'll just point out for your sake that what you posted doesn't say mass must be said in Latin, just that it doesn't need to be in a vulgar language.
The Roman mass has to be said in Latin. The Eastern rite masses are said in whatever language they were said in 300 years before Trent. That's why it says it can't be in the vulgar local language. There are problems with the local languages, e.g. the mass can be mistranslated and local languages tend to change over time. Latin and ancient Greek, not so much.
Cannon IX comes from this (Council of Trent, 22nd Session:
On not celebrating the Mass every where in the vulgar tongue; the mysteries of the Mass to be explained to the people.
Although the mass contains great instruction for the faithful people, nevertheless, it has not seemed expedient to the Fathers, that it should be every where celebrated in the vulgar tongue. Wherefore, the ancient usage of each church, and the rite approved of by the holy Roman Church, the mother and mistress of all churches, being in each place retained; [Page 158] and, that the sheep of Christ may not suffer hunger, nor the little ones ask for bread, and there be none to break it unto them, the holy Synod charges pastors, and all who have the cure of souls, that they frequently, during the celebration of mass, expound either by themselves, or others, some portion of those things which are read at mass, and that, amongst the rest, they explain some mystery of this most holy sacrifice, especially on the Lord’s days and festivals.