Incomplete question. I assumed you are referring to Fredrick Douglass Speech, “The Hypocrisy of American Slavery”.
Step-by-step explanation:
Remember, the term "vivid language" is used to an author's use of expressions that make his readers easily picture themselves in the experiences been narrated.
For instance, how an author describes a tragic event in their life or that of a character. In Douglass's Speech, he stated emphatically,
"Am I to argue that it is wrong to make men brutes, to rob them of their liberty,...to beat them with sticks, to flay their flesh with the lash, to load their limbs with irons, to hunt them with dogs, to sell them at auction, to sunder their families, to knock out their teeth, to burn their flesh, to starve them into obedience and submission to their masters?." We could note his clear use of the bolded vivid expressions to explain the experiences of African-American slaves.
He also stated, "I do not hesitate to declare, with all my soul, that the character and conduct of this nation never looked blacker to me than on this Fourth of July." The use of the adjective "blacker" gives a vivid description to the minds of his audience or readers how much he (Douglass) detest what had and was happening.