This article is about how literate people in anchient times always read out loud, proof being some roman being astounded by a scholar who read in silence and a few other times silent reading is mentioned as something strange. Why did reading silently become the norm? If someone would read out loud to themselves today you'd think they were brain damaged or mentally ill, even sounding the words in your mouth silently would make people think you're new to the whole text thing.
My theory is that some read words carry magic and 1000 AD someone put a spell on everyone and their future children to prefer silent reading so that magic isn't used. Who did that and why?