Throughout Gone With the Wind, black characters' speech is written with phonetic misspellings. Here's an example:
Miss Melly, den Ah know he los' his mine. He drunk an' he need sleep an' sumptin' ter eat but dat ain' all. He plumb crazy. (59.86)
The effect is to make the black characters appear uneducated, inarticulate, and childlike. Imagine for a moment if all the white characters talked this way. Here's Melanie talking about Rhett and his agony over Bonnie's death:
"Oh! Poor, poor Captain Butler!" she cried. "I'll go to him now, right away." (59.95)
She's so sensitive and concerned, right? And when she says she's go to him, she comes across as rising to the occasion, perhaps even taking charge. Now let's take this same exact moment and use the spelling Mitchell employs for the speech of black characters:
"O! Po'r, po'r Cap'n Butler!" she cried. "Ah'll go ter him now, r'ght 'way." (59.95)
Suddenly it's Melanie who seems uneducated and unsophisticated, talking from behind a barrier of ignorance and otherness.The use of dialect in literature is not inherently racist. Many authors, such as Zora Neale Hurston, employ dialect to capture nuanced forms of pronunciation. Mitchell presents what linguist George P. Krapp has called "Eye Dialect," a potentially racist use of dialect that presents variations in speech merely through misspelling, without paying attention to differences in pronunciation. Because it employs misspellings, "Eye Dialect" looks like dialect when reading, but does not actually sound like dialect spoken in the real world. The difference between "wuz" and "was," for instance, does not capture a difference in real-world pronunciation because both words sound the same when spoken. The difference in "dialect" is really just a difference in spelling, not sound. By employing "Eye Dialect" instead of the real sounds of spoken language, Mitchell makes Black dialect appear nothing more than the ignorant misspelling of standard (coded white) English, not an alternate pronunciation. Consequently, Mitchell's use of dialect makes Black people seem less than human, and by contrast, it makes white people seem more fully human; like they're people you can talk to and understand.
Mitchell uses dialect for various effects in the book. For instance, in the quote above, she has Mammy telling Melanie about how Rhett is reacting to the loss of his daughter. The result is intentionally precious or sentimental and moving; it's like having a child relate the story of a great tragedy, so that the innocence adds to the effect. Often, too, dialect is used for humor, as when Uncle Peter scolds Scarlett for not coming back to Aunt Pitty's house.
Ya'll nee'n try ter 'scuse yo'seffs. Ain' Miss Pitty writ you an' writ you ter come home? (30.24)
This is supposed to be funny because Peter, an ignorant servant, is upbraiding his superiors indignantly. The dialect emphasizes his silliness, and how incongruous it is for him to be yelling at them.
You Are Oppressed, Ha Ha
The scene is almost out of a blackface minstrel show, in which whites blackened their faces and then performed ridiculous skits based on the racist premise that black people were ridiculous. Such skits were still popular in the 1930s when Mitchell wrote her book, and Mitchell herself is writing in the voice of black people in order to make black people look ridiculous and inferior.
Uncle Peter's speech above, then, can be seen not just as influenced by blackface, but as actual blackface, with Mitchell pretending to be black, indulging in racist and dehumanizing stereotypes and "putting on" blackness, if you will, for her own amusement. She is in the vein of white people pretending to be black, using trivializing speech patterns taken straight out of minstrel shows.
The use of dialect to demonstrate black ignorance is especially painful because slaves were deliberately kept from obtaining an education, and there were even laws forbidding anyone from teaching slaves to read. So essentially, Mitchell is mocking Peter and Mammy for having been persecuted and oppressed. Stay classy, Mitchell.