premise: When Christianity was first established by law, a corrupt form of Latin had become the common language of all the western parts of Europe. The service of the Church accordingly, and the translation of the Bible which was read in churches, were both in that corrupted Latin which was the common language of the country. After the fall of the Roman Empire, Latin gradually ceased to be the language of any part of Europe. However, although Latin was no longer understood anywhere by the great body of the people, Church services still continued to be performed in that language. Two different languages were thus established in Europe: a language of the priests and a language of the people.
hypothesis: After the fall of the Roman Empire, people who had previously spoken Latin returned to their original languages.