In thank you mam which lines is a an example of dialect?

In "Thank You, Ma'am," the following line is an example of dialect:

"'Go wash your face,' she said. 'You dirty rascal.'"

The use of "rascal" and the phrase "go wash your face" are common expressions in African American Vernacular English (AAVE), which is the dialect spoken by the main character, Mrs. Jones.