Vatican Website translation:
29. Servers, lectors commentators, and members of the choir also exercise a genuine liturgical function. They ought, therefore, to discharge their office with the sincere piety and decorum demanded by so exalted a ministry and rightly expected of them by God’s people.
Consequently they must all be deeply imbued with the spirit of the liturgy, each in his own measure, and they must be trained to perform their functions in a correct and orderly manner.
29. Etiam ministrantes, lectores, commentatores et ii qui ad scholam cantorum pertinent, vero ministerio liturgico funguntur. Propterea munus suum tali sincera pietate et ordine exerceant, quae tantum ministerium decent quaeque populus Dei ab eis iure exigit.
Ideo oportet eos spiritu Liturgiae, suo cuiusque modo, sedulo imbui, et ad partes suas rite et ordinate obeundas institui.
Slavishly literal translation:
29. Those serving, readers, commentators, and those who relate to the schola of singers also perform a liturgical ministry. Therefore they should exercise their office/task with that sincere piety and order that befits such a ministry and that the people of God properly expect of them.
Therefore it is necessary for them, each according to his own [proper] mode, to be profoundly filled with the spirit of the Liturgy and to be instructed for performing their [proper] parts correctly and in a[n] [well-]ordered fashion.
From a general consideration of how all liturgical ministers, ordained and non-ordained, are to manifest the hierarchical and communitarian character of the liturgy as signs, the Council Fathers turn their attention to liturgical ministry exercised by the non-ordained. It is significant that they declare that servers, lectors, commentators, and music ministers exercise a genuine liturgical function and are not simply substitutes for clerics, when said clerics are unavailable. Most probably this declaration comes from a deepened understanding of the role of baptism (and confirmation) as foundational to all liturgical ministry.
We can trace the development of this thinking in the case of choir members from Tra le sollecitudini (1903) that declared in its article 12: “With the exception of the melodies proper to the celebrant at the altar and to the ministers, which must be always sung in Gregorian Chant, and without accompaniment of the organ, all the rest of the liturgical chant belongs to the choir of levites, and, therefore, singers in the church, even when they are laymen, are really taking the place of the ecclesiastical choir.” From this it was deduced that a genuinely liturgical choir could only consist of men and boys, since only they were potential clerics, legislation technically in force until the 1958 Instruction on Sacred Music and Liturgy. SC art. 28 makes it clear that both men and women (presumably by reason of their baptism [and confirmation]) exercise a genuine liturgical function when they exercise music ministry.
Having clarified the genuine ministry exercised by non-ordained members of the baptized, the Council Fathers turn their attention to the proper intellectual and spiritual formation for servers, readers, commentators, and those in music ministry.
Pray Tell readers may wish to reflect on how these non-ordained liturgical ministries have developed and been exercised over the past fifty years. (E.g., the role of the commentator, presumably important to help worshipers engage the Latin language liturgy “fully, consciously and actively” at the time of the Council, has almost completely disappeared from liturgical celebrations in the vernacular.) They may also wish to discuss what kinds of formation are available for these non-ordained ministries and how effective they have been in inculcating liturgical piety and imparting practical knowledge of the rites.