The classic apologetics collection published under the title Radio Replies, by Fathers Rumble and Carty, was originally published in 1938. The three volume set is eminently readable and still relevant (hardly surprising when the subject is Catholic truth that cannot change), formatted as questions-and-answers taken from a series of apologetics radio broadcasts.
As part of our effort to assist the faithful and successful implementation of Summorum Pontificum, we will be called upon to answer the above question-- "Why Latin?" I thought it fitting, since the Mass' critics accuse us supporters of trying to turn back the clock, that I check the answers given in Radio Replies. Below are some excerpts:
1392. Why, in all ceremonies and sermons, do priests speak Latin?
In the Epistle to the Hebrews, V., I., you will find these words, "Every Priest is ordained for men in the things that pertain to God, that he may offer up gifts and sacrifices for sins." A Priest has two chief duties: to offer sacrifice to God, and to sanctify men by his teaching and instruction. Now, when a Priest is speaking, not to men, but to God in the name of men, he speaks in the language of the Church-- in Latin-- a language God certainly understands, as does the Priest. When on the other hand he speaks to the people he speaks in their own language... Sermons are always given in the vernacular, and not in Latin, because they are addressed to the people. Go into any Catholic Church, and you will never hear any sermons in Latin.
1393. But the Priest says the Mass in Latin.
That is a sacrificial action offered to God. Latin is the liturgical language of the Catholic Church, just as Hebrew is the official language still used in the Synagogue.
1394. Do the worshippers understand all that the Priest says in the Latin Mass?
Not all Catholics understand Latin, by any means. But they are all quite at home when assisting at Mass. They know what is being done, even though they cannot understand all that is being said... However, every Catholic can know what the priest is saying, should he wish to do so. He has but to secure a prayer book containing the translation of the Latin into English. Most prayer books [missals] give the Latin and the English of the Mass side by side, in columns.
1395. Why does the Church cling to Latin, a dead language?
For one reason, precisely because it is dead! In modern and living languages, words are constantly changing their meaning whilst in a dead language, such as Latin, they do not. The essential doctrine and significance of Christianity must not change, and the safest way to preserve it intact is to keep it in an unchangeable language. Again, a universal Church must have at least her chief form of worship in a universal language. Christ came to save all men, and wherever a member of the true Church may be in this world he should be able to find himself at home at the central act of Christian worship. The Mass, being said in Latin, is the same in all lands...It brings out the wisdom and the universality of the Catholic Church. The Priest ascends the Altar to intercede with God on behalf of the people. Those present kneel, and in their hearts pour out their prayers for their own necessities. They feel no more need to know just what the Priest is saying than the Jews who knelt at the foot of the mountain felt the need of knowing just what Moses was saying to God on their behalf at the top. (And from what can only be described as better days, comes this:) ...if anyone should complain of the use of Latin, it should be those who have to endure it. And I have never yet heard a Catholic soul complain that it caused difficulty, or that he or she would like it changed.
1396. What good can result to the people if they cannot know what the Priest is asking in their name?
[After reiterating that they can know by using a Missal] ... the Latin prayers could [still] win for them the graces requested. If a German friend prayed for you in German, would that prayer be useless because you did not understand German?
1397. Is it not a short-sighted policy, since God hears hearts rather than words?
No. The Catholic Church is the greatest Church of all, and has preserved her unity despite her vast expansion. Those smaller churches, on the other hand, which adopted national languages are divided one from the other; are national in character; and are splitting up into innumerable sects as their doctrines change with every change in the sense of modern words.