Although "Babel-17" is set in a future with starships, reanimated consciousnesses, extreme body modifications, advanced weapons, and interstellar conflict with alien cultures, it is not so much a story about any of these things as it is a story about language and understanding.
Rydra Wong, the main character, is a genius at understanding spoken languages. She can also read attitudes and at times entire trains of thought from body language. She is enlisted to decipher a new language (Babel-17), and her journey to understand the language and the mindset it implies takes her far in both space and understanding.
It's a short book, and has a nice focus to it. Delany gives a lot of detail about the characters and their communication to give the book a nice depth, but goes light enough on the details about the technology and environments that the reader's imagination can fill in the details. With very few exceptions, the low level of tecnnical detail helps avoid dating the book, which stands the test of time quite well.
Very enjoyable and a quick read, highly recommended.