Many identify "Speech Sounds" as an allegory for the Cold War, which pitted the U.S. against the U.S.S.R. amid the rise of nuclear technology. The Cold War ended a few years after Butler wrote the story. Writers often responded to these uncertain times by turning to the speculative nature of genre fiction, particularly science fiction and post-apocalyptic fiction (which often dealt with the nuclear, a topic Butler was particularly worried about).
In "Speech Sounds," Butler uses the pandemic to as an allegory for how the ideological Cold War often generated suspicion in America about the safety of communication, spurring the idea that anyone could be listening or watching. The speed and force of the pandemic cause a lack of direct communication:
As it swept over the country, people hardly had time to lay blame on the Soviets (though they were falling silent along with the rest of the world), on a new virus, a new pollutant, radiation, divine retribution....
The Soviets' and other nations' silence only amplifies Americans' paranoia, as a lack of speech means a lack of opportunities to slip or to reveal oneself as guilty. Because no one can talk, almost everyone is keeping secrets, and Americans begin to turn on not only other nations but themselves. This infighting can be seen on the Washington Boulevard bus at the beginning of the story. In these ways, "Speech Sounds" reflects Butler's childhood in the height of the Cold War, when the fear of the unknown became deadly. In the end, though, the story also communicates hope that humans can come together again.