LATIN has been, and remains,  the official language of the Roman Catholic Church.  The official  language of the Church's liturgical texts and rites is also - still - Latin. 

But,  after the Second Vatican Council, the "vernacular "(the language of a particular people) was permitted.  The reason for the change from a long tradition of Latin liturgy was that it was thought that people might be better able to participate in liturgical worship. The change was gradual, but eventually, each language group had its own set of liturgical texts. 

The Church recently promulgated a new Latin version of the Bible,  the "Nova Vulgata",  and the Psalter, the "neo-vulgate",  is taken from that version.  At the same time, other versions of the psalms, for several reasons, have been used alongside the current Psalter, for varying lengths of time: some since the 4th century, and one, since 1945.

The "neo-vulgate" is the "official" translation at this time, but the standard "Vulgate" or "Gallican" Psalter (which was termed the official Psalter in the 16th century) is also still in use, as is the Psalter of Pius XII,  called the "Psalterium Vaticanum" or  "Novum Psalterium" and the "Romana", which is the first translation made by St. Jerome in 383.