The Holy See has every obligation to use Latin as its official language and, in theory, could change its practice. However, such a change appears unlikely in the foreseeable future. As a language no longer in common use (a dead language, though some would dispute the exactness of this description), Latin has the advantage that the meaning of its words have less likelihood of changing radically from century to century. This helps to ensure theological precision and to safeguard orthodoxy. Accordingly, recent Popes have reaffirmed the importance of Latin for the Church and in particular for those undertaking ecclesiastical studies.
Especially since the Second Vatican Council of 1962–1965, the Church no longer uses Latin as the exclusive language of the Roman and Ambrosian liturgies of the Latin Rite Catholic Church. As early as 1913 the Catholic Encyclopedia had already commented on the beginnings of the replacement of Latin by vernacular languages—but the Church still produces official liturgical texts in Latin, thus providing a clear single point of reference for translations into all other languages. The same holds for the official texts of Canon law.
After the use of Latin as an everyday language died out even among scholars, the Holy See has for some centuries usually drafted papal documents and the like in a modern language, but the authoritative text—the one published in the Acta Apostolicae Sedis—generally appears in Latin, even if this text becomes available only later. For example, the writers of the Catechism of the Catholic Church drafted it in French, and it appeared first in that language in 1992. But five years later, when the Latin text appeared in 1997, the French text had to undergo correction in line with the Latin version.
Occasionally, the official texts come out in a modern language. The best-known such include the motu proprio Tra le sollecitudini (1903) by Pope Pius X (in Italian), and Mit brennender Sorge (1937) by Pope Pius XI (in German).
The rule now in force on the use of Latin in the Eucharistic liturgy of the Roman Rite states: "Mass is celebrated either in Latin or in another language, provided that liturgical texts are used which have been approved according to the norm of law. Except in the case of celebrations of the Mass that are scheduled by the ecclesiastical authorities to take place in the language of the people, Priests are always and everywhere permitted to celebrate Mass in Latin" (Redemptionis Sacramentum, 112).
In most countries, those who speak Latin for liturgical or other ecclesiastical purposes use the pronunciation that has become traditional in Rome, giving the letters the value they have in modern Italian, but without distinguishing between open and close E and O. AE and OE coalesce with E, and before these and I the letters "C" and "G" take the sounds of English CH and J respectively. "TI" followed by a vowel is generally pronounced as /tsi/ (unless preceded by "S", "T" or "X"). Such speakers pronounce consonantal "V" (not written as "U") as in English, and double consonants are pronounced as such. No distinction is made between long and short vowels.
However, ecclesiastics in some countries follow slightly different traditions. For instance, in Slavic countries and in German-speaking ones the letter "C" before the front vowels /e/ and /i/ commonly receives the value of /ts/ and speakers pronounce "G" in all positions hard, never as English J. (See also Latin regional pronunciation and Latin spelling and pronunciation.)
A Vatican institution, the Latinitas Foundation, exists to promote the use of Latin not only in Church documents but in all facets of modern life.
Initiatives of the Latinitas Foundation include the publication (in Italian) of the 15,000-word Lexicon Recentis Latinitatis (Dictionary of Recent Latin), which indicates Latin terms to use in referring to a bicycle (birota), a cigarette (fistula nicotiana), a computer (instrumentum computatorium), a cowboy (armentarius), a motel (deversorium autocineticum), shampoo (capitilavium), a strike (operistitium), a terrorist (tromocrates), a trademark (ergasterii nota), an unemployed person (invite otiosus), a waltz (chorea Vindobonensis), and even a miniskirt (tunicula minima) and hot pants (brevissimae bracae femineae). Some 600 such terms extracted from the book appear on a page of the Vatican website.
Latin remains the official language of the Holy See and Vatican City. The Latin letters department of the Vatican Secretariat of State (formerly a part of the Secretaria brevium ad principes et epistolarum latinarum) is entrusted with the task of translating into Latin or correcting the Latinity of the writings of the Supreme Pontiffs and curial documents. The celebrated Latinist, Fr. Reginald Foster, O.D.C., works here. Up until the 1960s Roman Catholic priests studied theology using Latin textbooks, and the language of instruction in many seminaries was also Latin. The use of Latin in pedagogy and in theological research, however, has since declined. Latin was still spoken in recent international gatherings of Roman Catholic leaders, such as the Second Vatican Council, and is still used at conclaves to elect a new Pope. The Tenth Ordinary General Assembly of the Synod of Bishops in 2004 was the last to have a Latin language group for discussions. Although Latin is the traditional liturgical language of the Roman (Latin) Church, the liturgical use of the vernacular has predominated since the liturgical reforms which followed the Second Vatican Council.
In 1976 the Latinitas Foundation (Opus Fundatum Latinitas) was established by Pope Paul VI with the aim of promoting the study and use of Latin. The foundation publishes a quarterly in Latin, Latinitas.