Howard Jacobson, in his Independent column a while back
It is a universal law that people give a bad account of themselves when they speak. They cannot find the words for what they truly feel. At a loss, they say what someone else has said, or what they think they should say, and end up parodying what is in their hearts.
Hence the need for literature.
As with what they speak, so with what they hear. Which is why you will find so many intelligent people prepared to listen to and read material that is beneath them. It is as though aesthetically and linguistically we lag behind our own natures. Thus we see adults who have thought long and felt deeply squandering themselves on Harry Potter.
Hence the need to teach literature.