Symbolism, Imagery, Allegory
There is an awful lot of silence in Black Boy. Since books are basically the opposite of silence—they’re all about words—it’s notable that Black Boy brings up "silent" and "silence" almost 100 times. If an author does something enough, it probably means something. Something like…
When Richard starts asking the difficult questions, he realizes that his security clearance doesn’t get him very far. It’s like a big conspiracy of disinformation.
When Richard asks his mom about race, she mostly non-answers and he’s frustrated to think that there’s a reality "beneath all the words and silences" (1.2.142). When his grandpa dies, he can’t go to the funeral and he says, "They told me nothing and I asked no questions" (1.5.231). Even when he asks about "Professor" Matthews, the only answer Richard finds is more silence: "it’s something you can’t know" (1.2.423).
As he grows older, Richard realizes that it’s not just his family: whenever he asks the boys he works with about race, "they would either remain silent or turn the subject into a joke" (1.7.125).
The whole world seems complicit in a conspiracy to keep him from understanding anything about his life.
A Secret Language
But there’s another kind of silence, too. A telepathic kind. Richard explains: "That was the way things were between whites and blacks in the South; many of the most important things were never openly said; they were understated and left to seep through to one" (1.8.7).
Time after time, Richard "talks" to white men through silence. And it makes sense. Since blacks and whites more or less speak different languages in the South—maybe silence is the only way they can communicate.