latin+answer

"At the present time there are in Britain, in harmony with the five books of the divine law, five languages, and four nations-English, British, Scots, and Picts. Each of these have their own language, but are all united in their study of God's truth by the fifth, Latin, which has become a common medium through the study of the scriptures."

Here Bede is saying that the study of the scriptures unites all the people because Latin is the universal language used. When writing this, he also wanted this writing to be read by many generations after him so he had to write it in a language that could be translated by anyone.