Why could some people not understand Catholic Church services?

Answer 1

A Catholic Church service would be Lauds (Morning Prayer), Vespers (Evening Prayer), these services are usually only held in monasteries or religious settings, so I would assume that a visitor might not be all that familiar with them. Other services would be Benediction, Adoration, things of that sort, which I'm sure that everyone understood. Unless you are using the word "service" like a protestant to refer to the Mass (the Eucharist) which used to be in Latin. In that case, your question might arise because the Mass in the West was usually said in Latin, but, even in that case, the only one who wouldn't understand would be a non-Catholic visitor as everything in the Mass was very familiar and you learned about it from infancy. The prayers, even in Latin, would be familiar. I can still say the Our Father (the Lord's Prayer) and the Hail Mary in Latin. The readings were repeated in English (or whatever the common language of the people was, which is why we had Polish parishes, Italian parishes, Slovak, parishes, etc.) The sermon would be in the vernacular. Everyone understood from infancy that they were at the sacrifice of Our Blessed Lord on the Cross, and the re-presentation of the Last Supper, we all made an Act of Contrition, and - if we were in a state of grace (had been to confession recently) would receive Holy Communion. But this, the Eucharist, was definitely NOT a "service", it was the Sacrifice of Our Blessed Lord for our salvation, and we were privileged to witness it, and to receive the graces from it.