legere (lat) to read => lectura (lat) the reading event => lecture (en) => lecturer (en) a person giving/hosting a reading event.
A lecturer is supposed to read the text of a book to students so that they are able to write it down and obtain a copy of it for themselves.
Books written by professional scribes are incredible expensive, and this new thing they established in Bologna in 1088 – the so called "universities" offering lectures will be a major breakthrough in the history of mankind to distribute knowledge!
Good to know some professors still honour the only true way of teaching.
Pfff this generation is wasting good expensive sheets of paper when good old oral tradition has worked for thousands of years. Writing was invented only 4000 years ago and still haven't caught on.