Vatican website translation:
40. In some places and circumstances, however, an even more radical adaptation of the liturgy is needed, and this entails greater difficulties. Wherefore:
1) The competent territorial ecclesiastical authority mentioned in Art. 22, 2, must, in this matter, carefully and prudently consider which elements from the traditions and culture of individual peoples might appropriately be admitted into divine worship. Adaptations which are judged to be useful or necessary should then be submitted to the Apostolic See, by whose consent they may be introduced.
2) To ensure that adaptations may be made with all the circumspection which they demand, the Apostolic See will grant power to this same territorial ecclesiastical authority to permit and to direct, as the case requires, the necessary preliminary experiments over a determined period of time among certain groups suited for the purpose.
3) Because liturgical laws often involve special difficulties with respect to adaptation, particularly in mission lands, men who are experts in these matters must be employed to formulate them.
40. Cum tamen variis in locis et adiunctis, profundior Liturgiae aptatio urgeat, et ideo difficilior evadat:
1) A competenti auctoritate ecclesiastica territoriali, de qua in art. 22 § 2, sedulo et prudenter consideretur quid, hoc in negotio, ex traditionibus ingenioque singulorum populorum opportune in cultum divinum admitti possit. Aptationes, quae utiles vel necessariae existimantur, Apostolicae Sedi proponantur, de ipsius consensu introducendae.
2) Ut autem aptatio cum necessaria circumspectione fiat, eidem auctoritati ecclesiasticae territoriali ab Apostolica Sede facultas tribuetur, si casus ferat, ut in quibusdam coetibus ad id aptis et per determinatum tempus necessaria praevia experimenta permittat et dirigat.
3) Quia leges liturgicae difficultates speciales, quoad aptationem, praesertim in Missionibus, secum ferre solent, in illis condendis praesto sint viri, in re de qua agitur, periti.
Slavishly literal translation:
40. Nevertheless while in places and circumstances, a more profound adaptation of the Liturgy may be sought, and therefore greater difficulty be avoided:
1) It is to be zealously and prudently considered by the competent territorial ecclesiastical authority (concerning which see article 22 § 2) which [elements], of that under consideration, from the traditions and genius of individual peoples could opportunely be admitted into divine worship. Adaptations, which are determined to be useful or necessary, are to be proposed to the Apostolic See, for introduction by its consent.
2) Moreover so that the adaptation be done with the necessary deliberation, faculty is granted to the same territorial ecclesiastical authority by the Apostolic See, if the case should require, to permit and direct in certain communities appropriate for this [purpose] and for a determined time necessary foreseen experiments.
3) Because liturgical laws are accustomed to carry with them special difficulties with regard to adaptation, especially in the Missions, in drawing them up men who are experts in the topic being treated are to be employed.
After articulating a rationale for liturgical inculturation in article 37, the Council Fathers sketched out what might be termed the “common” process of liturgical adaptation in articles 38 and 39. This process would apply when the cultural distance between the typical editions of the reformed liturgical books and the receiving cultures would not be too great (as, for example, would presumably be the case for Latin liturgical books received by contemporary worshipers in Italy employing the vernacular). Article 40 treats the situation in which a more “radical” adaptation would be needed (as, for example, might be the case in adapting the Latin liturgical books in Papua New Guinea for vernacular celebration). Articles 38-39 seem to foresee a “top-down” form of inculturation in which one begins (for the Roman Rite) with the reformed liturgical books, provides a vernacular translation of their content, and perhaps supplements that content with material particular to the culture or region (as, for example, when the Roman Missal for use in the dioceses of the United States includes a Mass formulary for July 4 “Independence Day”). Article 40 seems to foresee a “bottom-up” form of inculturation in which one begins with the religious practices of a given culture and attempts to find in them vehicles for Christian worship. (It should be noted that such processes had frequently taken place in the Roman Rite by “baptizing” or providing alternative ritual structures for established cultural patterns, e.g., the celebration of the Chair of Peter or of Advent fasting arising in response to the Saturnalia.)
Pray Tell readers might find it interesting to share their knowledge of how the more radical liturgical adaptations foreseen in article 40 have fared in the last 50 years.