In 1970, the Church allowed the entire Mass to be said in the local language, whatever that might be. Prior to that, the Mass had to be in Latin, the language of the Romans.
We have forgotten that our Chamorro people had been singing in Latin for many years. Even during Spanish times, the missionaries formed choirs that sang the Mass parts, like the Kyrie and Sanctus (Lord Have Mercy and Holy Holy Holy) in Latin. Besides the Mass parts (called the "Ordinary"), the choirs sang Latin hymns.
If outsiders back in the pre-war days thought Chamorros, as a whole, were isolated and ignorant, they did not understand that many Chamorros had a living connection with a faith, a culture and a language that went back to ancient Rome, through the Roman Catholic religion. Chamorros could sing in Latin, and sing music written by medieval monks and other composers.
This lady, who was in my choir years ago in Saipan, stil remembers a Latin Christmas hymn which she learned in the 1950s when she was a young girl, drafted into the choir by Tan Vicenta Lizama Evangelista. Tan Vicenta was older; born in the pre-war days. Tan Vicenta was taught by the Mercedarian Sisters from Spain who came to Saipan in 1928.
On Guam, Spanish priests in the 1920s were able to boast that the Hagåtña choir could sing half a dozen Masses, meaning the Mass parts sung to six or seven different musical scores; some Gregorian chant, some recent compositions.
Our mañaina (elders) knew more than we sometimes give them credit for.