I prefer the preface in The Adventures of Huckleberry Finn:
NOTICE
PERSONS attempting to find a motive in this narra- tive will be prosecuted; persons attempting to find a moral in it will be banished; persons attempting to find a plot in it will be shot.BY ORDER OF THE AUTHOR,
Per G.G., Chief of Ordnance.EXPLANATORY
IN this book a number of dialects are used, to wit: the Missouri negro dialect; the extremest form of the backwoods Southwestern dialect; the ordinary “Pike County” dialect; and four modified varieties of this last. The shadings have not been done in a haphazard fashion, or by guesswork; but painstakingly, and with the trustworthy guidance and support of personal familiarity with these several forms of speech.I make this explanation for the reason that without it many readers would suppose that all these characters were trying to talk alike and not succeeding.