The first document to take a quick look at is Sacrosanctum Concilium or the Constitution on the Sacred Liturgy. A bit misleadingly many say that this document is about getting the laity “more involved” in the liturgy. But that can be misinterpreted as making sure that they are doing more things. (Is the lector at Mass more involved that the person praying? Is the server more involved than the lector because he does more things?)
It does go on to set the norms for a restoration of the liturgy however to make the Mass more accessible. After highlighting the Mass as the most important touch point of our lives it sets out some norms and regulations on how the restoration should take place (not yet saying what exactly should take place in detail. That would come later.)
Here are some highlights:
48: “The faithful, when present at this mystery of faith, should not be there as strangers or silent spectators.” It goes on to explain that it is not necessarily talking about doing more things at Mass but fully participating at the Mass. The role of the lay person is extremely important. We come to offer ourselves as part of the sacrifice and then to be commissioned to bring Christ to the world. It is our duty to worship Him, to be taught by Him, and to fed by Him in order to accomplish this.
THIS IS NOT SAID IN THE DOCUMENT – this is me speaking: It is much the same for the priest. As a man he benefits when he too offers himself in this way, united as we all are in the Body of Christ for this is the most important benefit to the Body of Christ at the Mass.
So the rites are to be simplified, Scripture is to be used “more lavishly”, more care is to be given to the homily, the intercessions are to be restored, and “a suitable space may be allotted to the vernacular in the Masses which are celebrated with the people, especially in the readings and ‘the common prayer’” and to those parts which pertain to the people. 54
As you can see, Latin, far from being removed from the liturgy is still foreseen is being a norm while allowing space for the vernacular. In fact, the next paragraph it states, “Nevertheless, care must be taken to ensure that the faithful may also be able to say or sing together in Latin those parts of the Ordinary of the Mass which pertain to them.”
Communion under both species is then permitted but under very strict conditions such as at the First Mass of a newly ordained or for the newly baptized at the Mass which follows their baptism.