Whilst perusing the Infallible Wikipedia, I learned that the Venerable Bede was working on a translation of the Gospels into Northumbrian Englisc at the time of his death. Isolated parts of the Bible were often translated into Old English at the time, and (contrary to how it was in European nations) these were not always simply meant as guides for priests whose Latin was poor.
So, what if Bede decided to focus on writing a full Old English translation of the entire Bible instead of his Ecclesiastical History? What would be the effect of having a native-language translation be a tradition in later years, if we assume no butterflies?
(This would also freeze the Northumbrian-Englisc dialect of Bede's time in history if it proliferated, leading to this perhaps becoming an accepted archaic mode by the time of the Norman Conquest, like King James English is today).
I imagine the Normans might well try to suppress it on linguistic supremacist grounds even before the Catholic Church turned against native-language translations...