I might also point to a simple prophet like Amos. He among other things was a shepherd from Tekoa (not the highest status is it?) yet he seems to have a good knowledge of the countries around him, the law and Israel's history. He was before the Babylonian exile so back then obviously even the simple folk were able to get taught something. Of course also, while Amos probably didnt write the book himself someone must have been around (a scribe or someone) to write it down in such a small village (assumption which would fall apart if it was oral and then was written down when it reached a city or something)