Rydra Wong is a top linguist, acclaimed poet, and former military cryptologist. When the Alliance military come across a new code used by the enemy, which is beyond their ability to crack, they come to her for help. She informs them that it is not a mere code, but an actual language, and agrees to accept the challenge.
Quickly assembling a crew, Wong heads to the Alliance War Yards to study the raw data on this new language, which the military calls Babel-17. However, shortly after she arrives, an enemy attack forces her to flee in disarray, and she falls in with a privateer, who is, fortunately, on the Alliance side. Or mostly so.
On board the privateer's ship, she begins to learn more about Babel-17, and the surprising benefits and dangers it offers to someone who learns to speak it.
The novel earned Delany the first of his several Nebula Awards.
Tropes in this novel:
- Attack Pattern Alpha: The novel features a captain directing a fleet via clinical psychiatry terms. When the heroine grabs the mike off the captain and turns the tide of a battle by speaking to the ships in the same kind of language, she explains that it all made sense in the Babel-17 language she's been deciphering, indicating that there may be more to Babel-17 than just words.
- Bio-Augmentation: exotic, alien-looking "cosmetisurgery" is popular with spacecraft crews. Tails and feathers are common, but variety is the key, and some of the changes are quite disturbing. Those who aren't part of the Transport culture find it very distasteful.
- Brain Uploading: Spacecraft crew (and presumably others) who die are often able to go on serving as crew after death if they are able to have their brains uploaded. They are called "the deceased" and can only interact via computer interfaces, but can still be valued crew members.
- Conlang: Babel-17 itself is an in-universe example. It is a language specifically constructed to take advantage of the Language Equals Thought trope. Learning Babel-17 has significant effects on the way you think. When Wong first starts to learn the language, she finds it makes certain kinds of strategy puzzles much easier to solve. Later, she also finds it has some additional not-so-pleasant effects.
- Culture Clash: The culture of the people who crew starships (Transport) has begun to diverge from mainstream culture to a startling degree. Transport folks mostly keep to themselves, and are looked down on by mainstream culture for their supposedly vulgar habits. The customs officer who has been assigned to help Wong put together a crew spends most of a chapter being shocked and/or terrified by what he sees of Transport culture.
- Cunning Linguist: Wong is an actual linguist, a poet, and generally a master of languages. She is able to recognize that Babel-17 is actually a language, and not just a code, after seeing just a few poorly transcribed examples.
- Curse of Babel: As Wong progresses in her study of Babel-17, she starts to find herself occasionally getting stuck in that mode at unexpected times, unable to revert her thinking back to a language her crew might understand. Thinking in Babel-17 helps her think strategically, but the mode appears to be somewhat addictive. And being a strategic genius isn't much good if you can't communicate your strategies to the people who need to implement them.
- Dark and Troubled Past: Since the book is set during a long-running war, there are several examples. Most notably:
- Rydra Wong, the protagonist, who lost both parents, and nearly died herself, when she was twelve. After she got out of the hospital, her near-telepathic understanding of people was often the source of more trauma.
- Butcher, one of the crew on the privateer, whose early memories are lost completely, but whose history is plainly quite unpleasant. The oldest memories he retains are of robbing a bank and killing several people. It wasn't until he got sent to prison that he begins to wonder why he even did such a thing.
- Enemy Within: The person who has been sabotaging Wong's mission turns out to be Rydra herself, who had been secretly programmed by simply learning Babel-17, and was completely unaware of any of it.
- Exotic Extended Marriage: Navigating through Hyperspace requires three people working extremely closely together and who know each other very well, so navigators, and eventually starship crews in general, have started to marry in threesomes; a habit which mainstream society still generally frowns on.
- Kiss Me, I'm Virtual: The customs officer who is helping Wong put together a crew for her ship is uncomfortable visiting the building where dead-and-uploaded personalities are housed, so he stays outside. While waiting, he is approached by a "succubus"—an uploaded personality who has learned to charm and seduce the living. When Wong returns, the officer is in a happy daze, until Wong points out that his wallet has been emptied.
- Language Equals Thought: The novel is built wholly around this trope. The smallest (and least spoilish) example is a race of aliens whose language is based almost entirely around temperature gradients but have no word for "house" - because of this, they build incomprehensible starships that look like a mass of strung-together boiled eggs. And of course, the eponymous language enables extremely fast thinking and enhanced spatial awareness.
- Logic Bomb: Discussed when the doctors are trying to come up with a way to get Wong and Butcher out of the mental trap they've gotten stuck in because of Babel-17. Several classic paradoxes are mentioned, including the Barber paradox, and the Cretan liar.
- Manchurian Agent: One saboteur turns out to have been programmed by Babel-17 itself, which is crafted to make people hate the Alliance.
- Recursive Canon: The book has an amusingly twisted example. Rydra Wong and her shipmate Ron start talking about "'Empire Star' and other Comet Jo stories", written by Muels Aranlyde, and Wong explains that Comet Jo is a real person who she knows, but that the stories are only loosely based on reality. Empire Star is actually a novella by Delany, and its protagonist is named Comet Jo. So you're left to wonder if Delany's novella is fact or fiction from the perspective of Babel-17's characters.
- Sherlock Scan: People often think Wong is telepathic from the way she answers unasked questions and seems to know exactly what they're thinking. She explains it as simply that her extraordinary gift for languages extends to body language, and at one point, gives a lengthy, detailed, and very Sherlockian explanation of the subtle clues that led her to anticipate what someone was about to say.
- Space Pirates: technically privateers, the crew of Tarik's Mountain are barely a step away from being full-blown pirates. They're generally on the Alliance side, but there are suggestions that they're not above a little opportunist looting of both sides in a pinch. Fortunately, when they rescue Wong's ship, the captain turns out to be a big fan of Wong's poetry, and therefore welcomes her and her crew.
- Strange-Syntax Speaker: One of the privateers, called Butcher, never uses the words "I" or "you". Which is strange to start with, but when Wong, the language expert, is intrigued, and decides to try and help him with this problem, the results are, at first, truly strange, as Butcher struggles to figure out how to use these words properly.
- Wall of Weapons: Baron Ver Dorco at the Alliance War Yards has his own hall of weapons. Of course, he is in charge of the War Yards, but when he takes Wong on a tour, it's clear that his interest is more than just professional, and edging into creepy.
- Virtual Ghost: Referred to as "the discorporate", people who die may (if circumstances are right) have their personalities transferred to machines. This is common on ship's crews, as many ship operations don't actually require a physical body.