Vatican website translation:
81 [sic]. In order that the divine office may be better and more perfectly prayed in existing circumstances, whether by priests or by other members of the Church, the sacred Council, carrying further the restoration already so happily begun by the Apostolic See, has seen fit to decree as follows concerning the office of the Roman rite.
87. Ut autem divinum Officium, sive a sacerdotibus sive ab aliis Ecclesiae membris melius et perfectius in rerum adiunctis peragatur, Sacrosancto Concilio, instaurationem ab Apostolica Sede feliciter inceptam persequenti, de Officio iuxta ritum romanum ea quae sequuntur placuit decernere.
Slavishly literal translation:
87. So that the Divine Office, whether by priests or by other members of the Church, may be better and more perfectly executed in those things connected to [present] realities, it is pleasing to the Most Sacred Council, pursuing the restoration happily undertaken by the Apostolic See, to decree the things which follow concerning the Office according to the Roman Rite.
Art. 87 represents the transition between the theological-liturgical rationale for changing the Roman Rite’s Liturgy of the Hours and the practical decrees implementing such change. It once again affirms that the Divine Office is not to be understood as a clerical prayerbook, but as a liturgy of the Church, intended for celebration by groups other than (but possibly including) priests. The Council Fathers acknowledge earlier reforms of the Office, probably most notably that of Pius X. Finally note that these decrees formally only apply to the Roman Rite, but one should remember that “[a]mong these principles and norms there are some which can and should be applied both to the Roman rite and also to all the other rites. The practical norms which follow, however, should be taken as applying only to the Roman rite, except for those which, in the very nature of things, affect other rites as well” (art. 3).
As Pray Tell readers consider the following practical norms, they may wish to indicate how the norms do or do not represent the theological-liturgical foundation offered earlier in the Constitution. They may also wish to share with readers the reformed Liturgy of the Hours presently found in the Ambrosian and Mozarabic rites, any of the Eastern rites, and the practices enshrined in the celebration of the Divine Office by canons and monks/nuns, as well as those marking lay communities.