So what are the “things that pertain to responsibility of the presider”? This sentence was added to the previous editions of the GIRM (see below).
Preparing liturgy is one of the most important tasks of everyone involved, presider, ministers, and assembly. Whatever mechanism for preparing liturgy a parish chooses (committee, advisory board, or the like), it needs to pay great attention to the rules of good communication and good liturgy. Three times between Paragraph 119 and Paragraph 122, Sing to the Lord cites GIRM 111, so it would be good to consult the entire text:
“111. Among all who are involved with regard to the rites, pastoral aspects, and music there should be harmony and diligence in the effective preparation of each liturgical celebration in accord with the Missal and other liturgical books. This should take place under the direction of the rector of the church and after the consultation with the faithful about things that directly pertain to them. The priest who presides at the celebration, however, always retains the right of arranging those things that are his own responsibility.” [my emphasis]
Note that the entire last sentence of 111 is new to this edition of the GIRM.
SttL 119 also quotes from a very important passage of the GIRM:
“352. The pastoral effectiveness of a celebration will be greatly increased if the texts of the readings, the prayers, and the liturgical songs correspond as closely as possible to the needs, spiritual preparation, and culture of those taking part. This is achieved by appropriate use of the wide options described below.
“The priest, therefore, in planning the celebration of Mass, should have in mind the common spiritual good of the people of God, rather than his own inclinations. He should, moreover, remember that the selection of different parts is to be made in agreement with those who have some role in the celebration, including the faithful, in regard to the parts that more directly pertain to each.
“Since, indeed, a variety of options is provided for the different parts of the Mass, it is necessary for the deacon, the lectors, the psalmist, the cantor, the commentator, and the choir to be completely sure before the celebration which text for which each is responsible is to be used and that nothing be improvised. Harmonious planning and carrying out of the rites will great assistance in disposing the faithful to participate in the Eucharist.”
This passage is echoed in the last paragraph of the GIRM that pertains to parishes:
“385. In the arranging and choosing of the variable parts of the Mass for the Dead, especially the Funeral Mass (e.g., orations, readings, Prayer of the Faithful), pastoral considerations bearing upon the deceased, the family, and those attending should rightly be taken into account. Pastors should, moreover, take into special account those who are present at a liturgical celebration or who hear the Gospel on the occasion of the funeral and who may be non-Catholics or Catholics who never or rarely participate in the Eucharist or who seem even to have lost the faith. For priests are ministers of Christ’s Gospel for all.” [my emphasis]
These last two sentences are an instance of the greatest principle in Canon Law: Salus animarum suprema lex, found in the last canon of the Code, Canon 1752: “ . . . and the salvation of souls, which must always be the supreme law in the Church, is to be kept before one’s eyes.”