The 1984 film Amadeus was junk for portraying Mozart as if he were an adult child. You often hear Dominus vobiscum in the Mass. It means, “May the Lord be with you.” If you recall the film, Star Wars, you heard the expression, “May the Force be with you.” Surprise!
The Sanctus at 48 minutes is loud. The composed Mass is dramatic throughout, which is fitting because it is the unbloody sacrifice, the living re-presentation of the Last Supper and the Crucifixion, the most magnificent and ongoing moment of salvation. It is offered for Mozart, and Lacrymosa, meaning tears, the last bit of music, suddenly ends. He was working on it on his deathbed and died before finishing.
The choir and soloists understand the Latin, and the musicians are filled with sorrowful joy at the consecration with heads bent down over their instruments. How much does the congregation understand at a Mass in Latin? Parts are repetitive and become easy after a while. My Missal lets me cheat because it has English and Latin side-by-side on every page. Altar boys here in Sacramento have the long and short responses memorized, including our little Gregory.