One can declare that praying in Latin is more efficacious than in another language by the importance placed upon it by the Church Herself in Her documents and by simple deduction.
By simple deduction, I mean what I posted about previously. The Church has established that Latin is Her official language. Who and What is the Church? The Bride of Christ. When the Church declares, Heaven also declares (see Matt. XVI). The authority to “bind and loose” is not one taken lightly. What is bound on earth is bound also in Heaven. Therefore, by following in step with the Church’s official declarations; whether they be disciplinary or doctrinal ie. a celibate priesthood, the doctrine of the Immaculate Conception, or Latin as Her official language, we celebrate these with the full Body of Christ. The Church Militant on earth who embraces these declarations, the Church Triumphant who celebrates them in heaven (Rom. CH. 8).
A few of the more prominent Vatican documents reveal that the Church has officially put into writing Her desire for Latin to be promoted, learned, and prayed. Pope Benedict XVI has urged the faithful to know their basic prayers in Latin (Sacramentum Caritatis, 62), Pope John XXIII promoted the study of Latin
Veterum Spientia, in
Sacrosanctum Concilium (SC 36. 1. Particular law remaining in force, the use of the Latin language is to be preserved in the Latin rites.) The common prayers during Mass are officially prescribed by the Vatican to be preserved in Latin (although today we still do not see this fulfilled).
Saint Augustine says of praying to our Lord, “He prays for us, he prays in us, and he is prayed to by us. He prays for us as our priest; he prays in us as our head; and he is prayed to by us as our God. Let us therefore recognize our voices in him and his voices in us” (Enarratio in Psalmum, 85: CCL 39, 1176).
By praying the Rosary in Latin we can unite ourselves with all of the Church’s declarations and affections towards this special language. If Christ, Who dwells intimately within the Church, and the Church, with Christ as the Head, holds dear this particular language, then it can only be more efficacious, while keeping this in mind, to pray in the intimate language of prayer bound by our Church between Heaven and Earth.
When a prayer is prayed in Latin with the devotion of realizing that it is done in a spirit of brotherhood with the Church Militant on earth as well as the Church Triumphant in Heaven. A devotion of brotherly love among Catholics throughout the Universal Church, a love for the Church which Christ established, a love for God’s Created Heaven and Earth where Latin is officially bound, a prayer done with this kind of devotion can only bring greater graces.
God bless, LC