"Hanna could neither read nor write"

Illiteracy is generally understood to be the inability of a person to read or write, as appears to be the case with Hanna.  There is also such a thing as functional illiteracy, which is where somebody may have a level of understanding but not enough to live a truly independent life.  There is evidence of a correlation between literacy and the probabilities of committing a crime, probably due to poor opportunities and low self worth.  This is not strictly the case with Hanna, due to the fact that the crimes she committed were part of a systematic and governing regime; however, the method of her recruitment shows how people of low education and prospects were ideal fodder for the SS.