At some point, during the reform period after the council, imprimatur authority (and that of some other matters) shifted to the  national Conference of Bishops.  Local bishops no longer had authority to approve vernacular texts which would be used in various liturgical celebrations.

And there was a shift in the official church's attitude in its translation policy.  In a letter to presidents of Conferences of Bishops (October 16th, 1964), Cardinal Lercaro, the head of the Consilium (the group responsible for preparing and putting into place all the reformed liturgical texts), said this: 

"The Consilium accordingly wishes to make known its mind on the special use of vernacular versions in regions using the same language: in these regions uniformity is to be maintained in the texts for vernacular celebration of the liturgy.  Approval of multiple versions, texts and editions in one and the same language, especially in such major languages as English, French, German and Spanish, seems ill-advised.....

The instructions, norms and regulations which followed since then regarding translations all specified that there should be one uniform translation of a liturgical text.

In 1965, National Conference of Catholic Bishops in the United States created a Secretariat for Liturgy. 
 

Somewhat later, the Bishops of English speaking countries joined to form the International Commission on English in the Liturgy (ICEL).  The ICEL would be responsible for translating the Latin liturgical texts into English.  The process would require years of work, as reforms of the various texts were made over a long period of time.  In addition, second editions would be required, eventually, and based on the editions coming from Rome, new texts would need to be prepared.
 

The question of the use of many translations for a single liturgical text was addressed several times. In 1970, the Sacred Congregation for Divine Worship (SCDW) issued norms (In confirmandis actis, Feb. 6,  1970)  for translations:

1.  There is to be a single vernacular version for:

a:  such parts of the liturgy as acclamations, responsories, and dialogues, which require direct participation by the congregation;

b.   the parts of the Order of Mass;

c. the psalms and hymns in the divine office  and the preces [intercessions] at lauds and vespers.

2.  For other texts a single vernacular version preferable;  nevertheless, where there is a true need, the individual conferences of bishops are empowered to make adaptations in the common translation or to make a new one.

3.  The texts mentioned in no. 1 must be approved by all the conferences of bishops obliged to its use [emphasis mine] before the Holy See confirms such texts

A particular point of these norms worth noting is # 3.  The scope of these norms is specific enough, but there is a caveat, as they require translations be approved by all the conferences of bishops obliged to its (the texts of # 1) use.  In terms of the office, for example, very few Roman Catholics in the United States (or in other English speaking countries) is "obliged" to use the "official" version of Liturgy of the Hours.  There seems to be a need for other translations for office texts prepared for those who aren't under obligation to pray them. 

The net result of all this is simple enough:  for texts of the Liturgy of the Hours, in the United States, the "official" versions require the use of the Grail (©1963) Psalm translation, the ICEL translations of prayers and other material, and the use of  NAB  texts for other Biblical material.

For those not obliged to pray the office, there are shorter versions called Christian Prayer (which contain all the day hours of the office) and Shorter Christian Prayer, which is an extracted version of Christian Prayer.

These texts are all approved.  The new edition of the Little Office of the Blessed Virgin Mary, because it uses the same translation material, is also approved for use by Catholics.
 

Not approved are those texts which use other versions of the Psalter, other versions of prayers, other versions of the Bible.  There are currently several "short breviary" texts in this category.  Where once the local Bishop could easily authorize a publication with his imprimatur, the Conference of Bishops, through the Secretariat of the Liturgy, has consistently maintained its authority over liturgical publications and has used the legal process when it was challenged.
 

It appears, now, that all texts which are classified as devotional and make use of material found in office books must be approved by the Bishops' Conference.  No diocesan Bishop may give his imprimatur to such a text. 
 

There may be several reasons for this: 

• the question of royalties - both the ICEL and the National Conference of Catholic Bishops lose royalty revenue when approved texts are not used; 

• the desirability of a uniform translation for any and all liturgical texts; 

• the prevention of theologically unsound text translations, etc.

At the same time, the ICEL  has been criticized and challenged by many for its translation work,   by English speakers who  use of the texts, and, of late, by Roman authorities, who, in 1998, required the Conference of Bishops to remove its imprimatur of approval from the ICEL's own version of the Psalter (1994).  It appears that changes to the ICEL process are now being addressed by the  executive committee of the ICEL Bishops.

Several newer versions of the Psalms are known as "inclusive";  this means that terms formerly treated as masculine are now more generalized. 

For example, 

• "Happy the man who walks......." has become "How happy are they who walk.....", etc.  

Some of these versions eventually become part of a printed text, but it is safe to say that, lacking the approval from the Bishops, they will not see a second edition.
 

Other issues appear here and there, but they aren't necessary for this study.
 

One "official"  book is necessary.  But as not everyone makes use of it, it seems beneficial to permit other versions of texts modeled on the official version.  There are many  who find another translation more comfortable and less problematic or difficult.  If the "Romana" version of Latin, used in St. Peter's basilica and in the Archdiocese of Milan (and perhaps a very few other places)  -  but not by everyone in the Roman Church - can co-exist with the other Latin psalm versions, why is not the same possible for English-speaking world?  Should those who prefer to use Latin be required to use   the "neo-vulgate", the "official" Latin text?  Should those in the United States who speak English be required to use ICEL and Grail texts for an office? 
 

During that very short period of time (from the end of 1963 to 1965 or so), there was a less complicated approach to translations, and that approach worked well, as Pope Paul himself had admitted.  With reference to the "short"  breviaries, there was variety and choice for many people not obliged to pray the full office.
 

Neither "approved" variety nor "approved" choice are in evidence today.
 

Here, again, is De Profundis, Psalm 129, in four of the current English versions of the Psalter.   The Grail version alone is  approved as "official" for  use in texts of the liturgy of the hours.