It is being increasingly taught in seminaries and there are special sessions offered all over the country to help priests learn the old Mass.
A priest who know no Latin can learn the old Mass in a year with hard work.
I’ve seen that too — there are online Latin Mass for Priests courses, it’s taught at the seminaries, there are old (Irish) priests (at our parish, anyway) who know it, and we have a feisty priest, young, who presides over the Latin Mass currently here in Los Angeles.
Any person who was ever an Altar Boy with the Latin Mass could certainly take on the priests role (with the caveat of actually being a priest), with just a little bit of study.
Somehow people from all over the world and in every culture learned how to say the Mass in Latin for over a thousand years before 1970. That includes not just Latins and their kin (French, Spaniards, etc.), but Germans, Estonians, Lithuanians, Scandanavians, Finns, Poles, Czechs, Berbers, Chinese, Indians, Arabs, Africans, Thais, Indonesians, Polynesians, American Indians, etc. Just the same as the Catholic Church of the East was able to teach Chinese, Indians, Persians, Turks, Mongols and others to say Mass in Aramaic when they held sway from Iraq to Japan from AD 500 to AD 1300.