Why does the priest say the words of the consecration in a low tone in the EF when Jesus probably did not say it in a low tone? In the Extraordinary Form of the Mass (the so-called &quot;Tridentine Mass&quot; or &quot;Latin Mass&quot;) the words of the consecration are said in a low tone. In the Ordinary Form they are said in what I think is called vulgar tone.
Why does the Priest say the words of the consecration in a low tone at the Extraordinary Form when Jesus probably did not say it in a low tone?
St. Robert Bellarmine, On the Most Holy Sacrifice of the Mass, ch. 12 &quot;Not everything in Mass must necessarily be said in a loud voice&quot;:

The next question is not much different from the previous one [&quot;On the Kind of Language&quot;], namely on the manner of voice. Our adversaries impugn the Latin Church because it bids many things in Mass to be said in a quiet voice, which was addressed in the Council of Trent, sess. 22 canon 9. There, from the beginning it must be observed that the question is not, “Whether it is licit per se to celebrate the whole Mass in a quiet voice”, for we are not unaware that the manner of voice does not pertain to the substance of the sacrifice, and these things can be changed according to the judgment of the Church. Thus, the whole question is placed in this: “Whether the custom of the Latin Church of pronouncing certain things in a quiet voice is opposed to the institution of Christ, and hence, is bad and necessarily must be corrected.”[…]2) The second objection: Christ did not institute the sacraments in such a way that the action would be visible and public, so the word, which is a special part of the sacraments, should be hidden and buried.I respond: The notion of a sacrament is one thing, and the notion of a sacrifice another; at the present we are arguing properly on the sacrifice. Moreover, the sacrifice does not consist in words, but in the oblation of a thing, words, however, are required in the sacrifice of the Mass, not to be themselves the sacrifice, or part of the sacrifice, but only to show the presence of the victim to us. By the words of consecration, as we showed above, it comes about that the Body of Christ is truly present on the altar; this is why the sacrifice will truly be outward and sensible, even if the words, whereby it comes about, cannot be heard. Add, that in the sacraments, to the essence of which the words chiefly pertain, it is not necessary that the words are perceived by those who receive the sacraments, provided they are perceived by those who minister them; otherwise baptism conferred upon infants, the insane, and the deaf would be invalid, which not even Chemnitz would admit. Consequently, we respond to the argument that Christ did not establish the words so they would be hidden and buried, that he also did not establish them in such a way that they must be pronounced to be heard by all who are present. Rather, he only established them to be really applied, and after him it was left to the liberty of the Church to constitute a manner of recitation. Not only do Catholics teach this, but even Chemnitz the teacher and Luther the prophet, in his book On the Formula of the Mass, where he permits the freedom to pronounce the words of the Supper in a loud or quiet voice.[…][To the objection that Eastern rites use a loud voice at consecration:]I respond: We do not deny that the words of consecration in the Eastern Church are customarily recited out loud, since it is quite certain from the liturgy of Chrysostom. Nor do we condemn this; for we do not contend that these words must necessarily be recited in a quiet voice, rather, that the Church is free to establish the rite, and hence neither the rite of the Greeks nor of the Latins can be condemned, nor should they. But although the words of consecration are uttered in a loud voice among the Greeks, nevertheless, certain others are pronounced in a quiet voice and clearly in secret, as we clearly showed from the same liturgy of Chrysostom. As a result, there is no need to respond to the testimony of Bessarion and Dionysius of Alexandria.


Rev. James Luke Meagher, How Christ Said the First Mass, p. 387:

The synagogue service was sung in a loud tone, while the table Seder was recited in a lower voice. The synagogue worship brought the Passover to the end of what we call the Preface of the Mass. During this first part of the Mass, the celebrant sings in a loud tone, while he recites the Canon in a low voice. Why is this? Some writers say the Canon is thus said in a low voice because of the persecutions of the Roman empire, and that then they said Mass in secret places and in a low voice lest enemies might hear them.But enemies would have heard the first part of the Mass which was always sung from the beginning when possible. The Orientals, not disturbed by Roman persecutions, sang the Mass from apostolic days, and therefore this does not seem a valid reason why the Canon is recited in a low tone. This Canon, found only in the Latin Liturgy, the Mass St. Peter established at Rome, is the most sacred part of the Mass, and corresponds to the sacred Seder of the Passover the Jews said at the table in a lower voice. St. Peter, leader of the apostolic band therefore established the Latin Liturgy with its Canon more according to the Jewish Passover Rite than the other apostles, who established Liturgies of the Mass indifferent languages.