The language of any Church or rite, as distinct from the vulgar tongue, is that used in the official services and may or may not be the common language. For instance the Rumanian Church uses liturgically the ordinary language of the country, while Latin is used by the Latin Church for her Liturgy without regard to the mother tongue of the clergy or congregation. There are many cases of an intermediate state between these extremes, in which the liturgical language is an older form of the vulgar tongue, sometimes easily, sometimes hardly at all, understood by people who have not studied it specially. Language is not rite. Theoretically any rite may exist in any language. Thus the Armenian, Coptic, and East Syrian Rites are celebrated always in one language, the Byzantine Rite is used in a great number of tongues, and in other rites one language sometimes enormously preponderates but is not used exclusively. This is determined by church discipline. The Roman Liturgy is generally celebrated in Latin. The reason why a liturgical language began to be used and is still retained must be distinguished in liturgical science from certain theological or mystic considerations by which its use may be explained or justified. EACH LITURGICAL LANGUAGE WAS FIRST CHOSEN BECAUSE IT WAS THE NATURAL LANGUAGE OF THE PEOPLE. But languages change and the Faith spreads into countries where other tongues are spoken. Then either the authorities are of a more practical mind and simply translate the prayers into the new language, or the conservative instinct, always strong in religion, retains for the liturgy an older language no longer used in common life. The Jews showed this instinct, when, though Hebrew was a dead language after the Captivity, they continued to use it in the Temple and the synagogues in the time of Christ, and still retain it in their services. The Moslem, also conservative, reads the Koran in classical Arabic, whether he be Turk, Persian, or Afghan. The translation of the church service is complicated by the difficulty of determining when the language in which it is written, as Latin in the West and Hellenistic Greek in the East, has ceased to be the vulgar tongue. Though the Byzantine services were translated into the common language of the Slavonic people that they might be understood, this form of the language (Church-Slavonic) is no longer spoken, but is gradually becoming as unintelligible as the original Greek. Protestants make a great point of using languages "understanded of the people", yet the language of Luther's Bible and the Anglican Prayerbook is already archaic.
History
When Christianity appeared Hellenistic Greek was the common language spoken around the Mediterranean. St. Paul writes to people in Greece, Asia Minor, and Italy in Greek. When the parent rites were finally written down in the fourth and fifth centuries Eastern liturgical language had slightly changed. The Greek of these liturgies (Apost. Const. VIII, St. James, St. Mark, the Byzantine Liturgy) was that of the Fathers of the time, strongly coloured by the Septuagint and the New Testament. These liturgies remained in this form and have never been recast in any modern Greek dialect. Like the text of the Bible, that of a liturgy once fixed becomes sacred. The formulæ used Sunday after Sunday are hallowed by too sacred associations to be changed as long as more or less the same language is used. The common tongue drifts and develops, but the liturgical forms are stereotyped. In the East and West, however, there existed different principles in this matter. Whereas in the West there was no literary language but Latin till far into the Middle Ages, in the East there were such languages, totally unlike Greek, that had a position, a literature, a dignity of their own hardly inferior to that of Greek itself. In the West every educated man spoke and wrote Latin almost to the Renaissance. To translate the Liturgy into a Celtic or Teutonic language would have seemed as absurd as to write a prayerbook now in some vulgar slang. The East was never hellenized as the West was latinized. Great nations, primarily Egypt and Syria, kept their own languages and literatures as part of their national inheritance. The people, owing no allegiance to the Greek language, had no reason to say their prayers in it, and the Liturgy was translated into Coptic in Egypt, into Syriac in Syria and Palestine. So the principle of a uniform liturgical language was broken in the East and people were accustomed to hear the church service in different languages in different places. This uniformity once broken never became an ideal to Eastern Christians and the way was opened for an indefinite multiplication of liturgical tongues. [2]
The principle of using Latin in church is in no way fundamental. It is a question of discipline that evolved differently in East and West, and may not be defended as either primitive or universal. The authority of the Church could change the liturgical language at any time without sacrificing any important principle. The idea of a universal tongue may seem attractive, but is contradicted by the fact that the Catholic Church uses eight or nine different liturgical languages. Latin preponderates as a result of the greater influence of the Roman patriarchate and its rite, caused by the spread of Western Europeans into new lands and the unhappy schism of so many Easterns (see Fortescue, "Orthodox Eastern Church", 431). Uniformity of rite or liturgical language has never been a Catholic ideal, nor was Latin chosen deliberately as a sacred language. Had there been any such idea the language would have been Hebrew or Greek
*That encyclopedia entry was writen by Fr Asrian Fortescue, normally, a hero of those opposing Rome
The Church has never set up a mysterious unintelligible language as an ideal. There is no principle of sacerdotal mysteries from which the layman is shut out. In spite of the use of Latin the people have means of understanding the service. That they might do so still better if everything were in the vulgar tongue may be admitted, but in making this change the loss would probably be greater than the gain.
By changing the language of the Liturgy we should lose the principle of uniformity in the Roman patriarchate. According to the ancient principle that rite follows patriarchate, the Western rite should be that of the Western patriarch, the Roman Bishop, who uses the local rite of the city of Rome. There is a further advantage in using it in his language, so the use of Latin in the West came about naturally and is retained through conservative instinct. It is not so in the East. There is a great practical advantage to travellers, whether priests or laymen, in finding their rite exactly the same everywhere. An English priest in Poland or Portugal could not say his Mass unless he and the server had a common language. The use of Latin all over the Roman patriarchate is a very obvious and splendid witness of unity. Every Catholic traveller in a country of which he does not know the language has felt the comfort of finding that in church at least everything is familiar and knows that in a Catholic church of his own rite he is at home anywhere. Moreover, the change of liturgical language would be a break with the past. It is a witness of antiquity of which a Catholic may well be proud that in Mass to-day we are still used to the very words that Anselm, Gregory, Leo sang in their cathedrals. A change of language would also abolish Latin chant. Plainsong, as venerable a relic of antiquity as any part of the ritual, is composed for the Latin text only, supposes always the Latin syllables and the Latin accent, and becomes a caricature when it is forced into another language with different rules of accent.