Though Delany asserts he was a staunch believer in the Sapir Whorf hypothesis at the time he penned this, I'm skeptical to what degree he genuinely believed it. The hypothesis is that thought can only exist within the confines of a language. The novel takes it's name from an alien language central to the plot. Sometime in the far, space faring future, this language, Babel-17, is heard and recorded alongside various saboteur events, and it is up to the novel's telepathic, poet protagonist Rydra Wong to translate it and help the war effort. As Wong decodes the language she realizes it is more grammatically and semantically dense than any other human language, albeit without any trace of a first person pronoun. In accordance with the Sapir-Whorf hypothesis, this linguistic density allows people who can think in Babel-17 to gain a superhuman cognition. Delaney thankfully makes no effort to represent the language in the text, an absence which garners it some plausible mystique.

I find it curious that he utilizes a telepathic poet as a protagonist for the novel. In both cases, the protagonist is using a means to communicate beyond the ordinary limits of language. Via telepathy (in the text) it's a direct, unmediated understanding that circumvents language. With poetry, the protagonist is contorting and stretching language to express a feeling beyond the normal denotative meanings of the words. In both cases, thought is going outside the normal constrains of language and expressing something. It's as if Delaney needs to have the Babel-17 language exist to linguistically "reconfine" thought from its avenues of escape from language.