TIL:
Larger cities and churches employed their own scribe, but if you lived outside an urban area and you needed someone to copy a book for you, your first task was finding someone who could read and was willing to do the work. This was not an easy feat. Very few people could read and write in the Middle Ages. And the time required to copy a book would have drastically cut into a man’s day job. Researchers studying medieval manuscripts have often found errors and illegible writing that, they theorize, was because the scribe was actually illiterate and was only trying to copy the images of the words on the page without understanding the meaning.
https://curioushistorian.com/writers-cramp-the-life-of-a-medieval-scribe
Can anyone confirm?
I'm going to start first by pointing towards a response I wrote a couples months ago to a question regarding how expensive it was to train a scribe.
In that answer, I mention copying errors as well as discussing what "literacy" means in a medieval context--particularly in relation to Latin manuscripts (which the vast majority of medieval manuscripts were). Short answer: professional scribes were not illiterate in the modern sense (as in unable to actually read), although they might not be familiar with the nuances of specialist vocabulary in philosophical or theological treatises, or even just not great Latinists--which can lead to spelling errors, errors in correctly declining Latin verbs or getting nouns into the correct case. If you've ever dealt with Latin, you know that changing the case of a noun or a verb ending or tense can drastically change the meaning of a word. Tracing those errors through the transmission of various manuscripts is one way researchers can determine how multiple copies are related to each other.
Not all books were copied by professional scribes, however. At universities, books could be borrowed in sections (pecia) for copying by students--and sometimes these students made some pretty significant errors (or would even copy only the sections of a book they were most interested in--ran into that one personally during my examinations of manuscripts).
And the time required to copy a book would have drastically cut into a man’s day job.
Except for the students I mention above who might copy their own books, by the 13th century or so, scribes are trained professionals. They're either employed by churches and religious houses, or by secular workshops, or by government or private individuals as scribes or clerks. They do not have "day jobs". If you indeed "lived outside an urban area" and wanted to find a scribe to copy a book, you most certainly had wealth enough to hire a professional to do so.
As I did in the earlier reply, I highly recommend Raymond Clemens and Timothy Graham's Introduction to Manuscript Studies. It's a fabulous book for understanding how manuscripts were produced in the Middle Ages.