Jubilate Deo was a book of chants. The accompanying letter, as well as the book, were published (I believe) by the Sacred Congregation for Divine Worship, not the Pope himself.
That said, I don’t understand your “and yet,” which would imply that what I was stating was somehow wrong. Rather, I think Pope Paul VI’s vision was a Mass in which the majority of the spoken tongue was in English, with certain parts (such as the Credo, the Sanctus, the Agnus Dei, for example) sung/said/chanted in Latin. The implication therefore being that one should appreciate the need in our modern day for the use of the vernacular in Mass, while at the same time remembering our “heritage” and our history (of the Latin Rite).
I therefore either misunderstood your intent, or you misunderstood mine. If I misunderstood yours, then I’m sorry.