There is a difference between Latin being preserved and Latin being the only language used in the Latin rite. It’s not the same thing. Additionally, Br. David is correct. Armenia did celebrate the Tridentine mass in their language. Also, long before the Council of Trent there other languages were used in the Latin rite liturgical music. The prayers of the mass were in Latin, but much of the music was already in German, Italian and Spanish. In my own order we had Italian hymns written by St. Francis sung at mass from the 1200s.
Also, let us remember that the liturgy is not just the mass. It also includes the Liturgy of the Hours, which are equally important in the liturgical life of the Church. The Liturgy of the Hours were already being translated for use in some religious congregations, long before Vatican II. In addition, the OF is not a new rite. The Holy Father has said it quite clearly in Summorum Pontificum. The OF and the EF are two forms of the SAME RITE. They are not different rites. Therefore, the Latin Rite has not been changed. We simply have two forms of the same rite. Let’s not call it what it’s not. We have one Latin Rite mass, with two forms that are in general use. There are other forms that are used less commonly, but we do not call them rites. They continue to be the Latin Rite mass, for example the Carthusian form.
Fraternally,
Br. JR, OSF