The second installment of Gulf by Robert Heinlein appeared in the December 1949 issue of Astounding Science Fiction. It can be read here at Archive.org.
Robert Heinlein’s Spy-Fi thriller, Gulf, showed so much promise before sinking into the Campbellian morass of dull thinkery.
Whereas Part 1 featured covert cat & mouse action, high stakes interrogation, and a daring escape from a private jail by helicopter, Part 2 is devoted mostly to the characters explaining to the protagonist about the next step in human evolution: the man who is a better thinker. Lots of woo ensues.
These supermen have cooked up a special language in which phonetic sounds can convey the meaning of entire words and sentences, so a single word or sentence in smart-guy talk can convey encyclopedias of meaning, making thinkery that much more efficient. As a potential super-guy, the hero must be taught this language by a snarky dame.
The idea behind the language is that if you absorb and process information as a whole (such as a 10-digit number as a glyph rather than as a series of digits) you can retain more of that information. Except for smart-guy talk to work, I’d think you’d need a base language, since you’d have to be taught the complex idea which the single phonetic syllable was supposed to represent. Anyway…
Heinlein eventually remembers that he was writing a spy thriller, so the last three page are devoted to the hero and the dame who taught him smart-guy-talk going to the villain’s moon-palace, and they stop her from blowing up the earth. The hero and the dame both die in the explosion, but not before they get married over the radio. The end.