In the article "The Language of Paradox," author Cleanth Brooks argues that poetry is made up of a language of paradox, meaning that poetry is made up of a "dynamic balance of opposing ideas, attitudes, and feelings" ("Cleanth Brooks' 'Language of Paradox'"; "Literary Formalism"). In his essay, Brooks particularly cites Wordsworth as an example:
It is a beauteous evening, calm, and free,
The holy time is quiet as a Nun
Breathless with adoration ... (as cited in "Literary Formalism")
Brooks particularly explains that there is a contradiction between the words "breathless" and "calm" and "quiet." As Brooks argues, the word breathless "suggests excitement" but Wordsworth has described the evening as both quiet and calm (as cited in "Literary Formalism"). He further argues that these contradictions in words arise because "language is too vague" for poets to be able to express their intended messages without creating paradoxes; poets must "make up" their own language as they go along, which creates paradoxes (as cited in "Cleanth Brooks' 'Language of Paradox'").
Based on Brooks' idea, it seems we certainly can see paradoxes in all poetry, even African-American poetry. Let's look at Langston Hughes' poem "Democracy" as an example. We can see one contradiction in the very first line, "Democracy will not come." It can be argued that democracy, as a form of government, is really something established or created rather than something that "come[s]." To come means to arrive; it can't truly be said that democracy is something that simply arrives. However, Hughes, wanting to portray the African-American race as waiting for the full freedom that's owed to them as American citizens, has created a paradox to juxtapose the freedom that is wanted with waiting.
We can further see a paradox in the last line of the first stanza, "... Through compromise and fear." The word compromise is a much less emotionally charged word than fear as compromise refers to coming to a mutual agreement, while fear, on the hand, describes unfortunate feelings caused by "impending danger, evil, pain, etc." (Random House Dictionary). Therefore, similarly to Brooks' Wordsworth example, the word compromise is a much more calming word, while the word fear is much more emotionally charged, creating a conflict, or paradox.