The linguist Charles Carpenter Fries strove to show how far classroom English diverged from what is actually standard English, both in speech and writing. In The Story of Ain't (reviewed yesterday), David Skinner describes how Fries set out to establish this through empirical evidence, a corpus study of three thousand letters written to the U.S. government by ordinary citizens. He developed this analysis in a book, American English Grammar, demonstrating that "the actual difference in underlying grammar between vulgar and standard was, in reality, quite small."
After dispatching the manuscript to the publisher, he waited for twelve months. Skinner reports: "The revised manuscript came back, and it was a shock to look at. Every single instance of uneducated grammar that Fries had quoted in his study--hundreds of passages painstakingly transcribed from those handwritten letters--had been corrected for grammar and usage by some well-meaning copy editor."