A translated vernacular Mass was never on offer. The Bugnini boys of Concilium, after the deceptive Sacrosanctum Concilium of 1963, were able to proceed full tilt at their alleged update as SC permitted any change considered suitable. The alternative Congregation of Divine Worship update to the Mass was increasingly discarded. The point is that these Modernists were working in and through Latin on the ordinary and propers. Cardinal Cushing was one of the few sitting at the Council with poor Latin, so poor he needed translators. The translations of the International Committee on the English Language and others, was done mostly after the fact, although a good many English language errors emerged with the transitional Missal between 1963 and 1969. Anyhow the hieratic Book of Common Prayer high Jacobean English does not really have a counterpart in other languages, as far as I am aware, I think there is maybe an older style of Polish, but there is no real fairly fixed 'olde style' vernacular in most places.

There were plenty of vernacular masses before V2 and even Mass in Mandarin was permitted by Clement XV. It would be heresy to say that the only masses that can be celebrated must be in vernacular. It is not heretical to say there should be masses said in vernacular.

I do not believe that there were  "plenty of vernacular masses" in the Roman Rite before the 20th century. 95% of the Catholics are Roman Rite. I do not believe that Clement XV authorized a Roman Rite mass in Mandarin. Catholics were not even allowed to use missals in his time. That sounds like a Novus Ordo smokescreen.

I do not believe that there were  "plenty of vernacular masses" in the Roman Rite before the 20th century. 95% of the Catholics are Roman Rite. I do not believe that Clement XV authorized a Roman Rite mass in Mandarin. Catholics were not even allowed to use missals in his time. That sounds like a Novus Ordo smokescreen.

Clement XI? There is no Clement XV, unless one of the minor, modern anti-Pope eccentrics are counted. Clement XI suppressed the so-called 'Chinese Rites.' The only real variant was the reversal of wearing hats. A priest in China would wear his hat on the altar, on account of the traditional understanding of hat wearing among the Chinese. Alexander VII had allowed Chinese in the liturgy. The only real exception regarding Latin for Latin Rite Christians were that native peoples in north America were permitted a substantial element of vernacular. Presumably their substantially nomadic culture might have created difficulty in creating a corp of native Indian priests using just Latin.