my understanding of history is the Catholic church wielded great power over the populace by having both literacy, but and also in Latin (a less accessible language). With 99 theses and a German bible people could easily get their religion on without the priestly class. This feels like a metaphor for what has happened in computing.
Latin was the most accessible langague in all of Eurasia from the time of the Roman empire until the start of industrial revolution. The Catholic church tought Latin to everyone who either became a member of the church, payed a small fee in either money or labor and in many cases for free.
People regularly went on pilgrimages to remote places all throughout Europe and perfectly understood each other, because nearly everyone could speak Latin. Even when the Portugese landed in China they were greeted in Latin.
At somepoint the upper classes started talking more and more in regional dialects and older languages, which then spread to the normal people. The church reacted pretty much immediately to this trend by requiring prayers and certain parts of the mess to also be conducted in these regional languages (somewhere around the 8th century, I think?).
What was low initially were the literacy rates, because books were incredibly expensive. Which didn't mean that the people couldn't read or write, just not to the degree necessary to read or copy the bible in Latin, which was the most available book at the time.
