"If you're using dialogue, say it aloud as you write it. Only then will it have the sound of speech."
Quote courtesy of Freewrite.
I had the pleasure of meeting his son when I was in the seventh grade - in my history class. Our teacher had gone to university with him and invited him to speak to our class. As part of that quarterly course we read Of Mice And Men. Considering this was a history class, I'd have thought Grapes of Wrath more appropriate.