This answer is taken from Fr. Bertrand Conway:
“Would not the people be better able to follow the services, if they were in the language of the congregation? Does not St. Paul condemn your Church’s use of Latin at Mass when he says: “Yet in the church I had rather speak five words with my understanding, that by my voice 1 might teach others also, than ten thousand words in an unknown tongue” (1 Cor. xiv. 19) ?
A Catholic of Richmond once told me that he answered this question put him by a Methodist minister by asking another: “Does not the Lord understand Latin?” A perfect answer, because it reminded his questioner that the Mass was a sacrificial action performed by the priest, as the representative of Christ, and, therefore, something utterly distinct from a sermon addressed to the people.
The language of the Mass prayers is in itself unimportant, for the Church has never found fault with the Eastern Churches for using other languages. Thus, for example, the Italo-Greeks of Southern Italy have said Mass in Greek for over a thousand years, while the Melkites of Syria, Palestine and Egypt use Arabic and Greek. The Byzantine rite is used by the Eastern Orthodox Church in fourteen different languages, but the Mass is the same in all.
Greek was originally the language of the Roman liturgy, Latin superseding it by the beginning of the fifth century. Conservative Rome and the nations of the West converted by her missionaries, retained the Latin tongue in the Mass, to strengthen the bond of unity, and to express her unchanging worship in an idiom free from the perpetual changes of the vernacular. Imagine Catholics of the twentieth century compelled to decipher an obsolete English liturgy of the days of King Alfred the Great!
Even the most ignorant Catholic knows the central part of the Mass, the Consecration of our Lord’s Body and Blood, and by constant attendance he soon comes to know the most important prayers which precede and follow it. Moreover, the whole liturgy is translated today in every language of the world, and books explaining its every part abound. While many intelligent Catholics read the Missal with the priest, this is not essential. One may attend Mass with profit and devotion by meditating on the Passion of Christ, by reciting prayers in honour of our Lady and the saints in union with Christ, or by reading a spiritual book.
