While those are important changes, Melchior’s question is whether the LOTH is “new” or the product of maturation. My position is that it is maturation, albeit rapid maturation, and that the precedent for radical change was established in 1910 and not 1970. In fact Pius X completely abolished the psalter of Pius V and made failure to use the new psalter grave matter.
The impact on the music for the Divine Office in 1910 was serious with the loss and rewording of many antiphons and the creation of new ones from obscure and unidentified sources. Matins was considerably shortened, and Lauds lost the 1500+ year tradition of always finishing the psalmody with the three Laudate psalms.
It’s been said that the LOTH was not designed to be chanted yet now books exist to chant the entire day office.
In achieving the goal of making the secular office more realistic for a busy and shrinking diocesan clergy, the LOTH succeeded. It achieved the same result for making it within reach of the laity, with a small but increasing number praying at least part of it.
This goal was the same one desired by Pius X with his 1910 reforms, and again by his successor Pius XII when he appointed Annibale Bugnini to study reform of the liturgy in the mid-40s.
Among other things evolution of the Divine Office allowed reciting Matins in anticipation the previous evening… a very clear precedent for the Office of Readings. For the latter the General Instructions are clear that it retains its nocturnal quality. This is supported by the rubrics that allow the use of the invitatory only at the Office of Readings or Lauds.
The lumping of all three mid-day Offices into one is perhaps one of the things I like the least about the LOTH (along with the NT canticle at Vespers). It’s almost a major hour like Vespers; in fact today the psalmody of this hour is as long as Vespers.
The issue of language bothers me least. The modern reality is that participation of the laity suggests the need for the vernacular. And the post-war expansion of Catholicism in non-European parts of the world suggests the same. Think for instance Korea, where Christianity is growing (Korea is proportionally the second Christian nation in Asia after the Phillipines), and yet where Latin is a major obstacle as Koreans have a different alphabet, different sounds, no clear roots in Latin and where Latin has zero cultural relevance. It’s the same issue as for the Mass, and it’s part and parcel of being a “universal” Church in a modern world.