I don’t have primary sources, but I have been told by people better informed that in Rome the liturgy was in Greek for many centuries before a Latin Mass began. Even in the traditional Latin Mass, there are portions which are still in Greek.
Also, the chants used to sound a lot more like what is today called Byzantine chant. The original Gregorian Chant followed many tonal qualities which are now exclusively associated with the Christian East. The period’s style is commonly referred to as
Old Roman Chant. You can listen to an example of this at the following link, which is very interesting as it is in Latin, but contains isons (sp?) and other methods of chant that are not now associated with Rome.
Title: “Graduale: Tecum Principium”.
Service: Mesonycticon (Midnight Mass)
Oh Rome, remember when you were Orthodox, and return to us…