A priest friend of mine, pastor of a parish in Chicago, told me that in that city, Mass is celebrated every Sunday in over fifty languages. ‘How would you cope with that situation?’ he asked. You will have guessed my answer: I would celebrate Mass in Latin. Nobody is fully at home in the Latin language, and consequently everybody can feel at home. Our multilingual church needs a language of unity. Think of Pentecost, when the heralds of the Gospel were heard by speakers of so many languages. In our day and in our country, Latin can foster unity and peace.
Pope Saint Paul VI, when he brought in the new Missal, expressed a wish that all Catholics of the Latin rites should be able to sing the Ordinary of the Mass ― the Gloria, Creed and so on ― in Latin to the traditional chants. His wish is far from being realised. But if you witness the forthcoming canonisation in Rome of Blessed John Henry Newman, with other beati of various countries and languages, you will see how Latin can unite a multilingual congregation. We have learned from experience that worshippers welcome Latin more readily if it is discreetly mixed with the vernacular. Hence the vernacular readings in the Mass.
(Mgr Bruce Harbert, Sermon given at the Association for Latin Liturgy’s Golden Jubilee Mass, 28 September 2019. Full text here)