As long as I'm pickin' nits -- the Sumerians invented cuneiform, but their language was an isolate, so no one could read it. Cuneiform's pronounciations were figured out using the known language of Persia (glad I finally looked this up, I'd forgotten this) by 1849. Akkadian, a Semitic language (extinct but related to living Semitic languages) followed.
Written Sumerian persisted well after the Sumerians themselves either abandoned their language or were culturally absorbed or wiped out, or some combination, perhaps 1000 years after they'd invented cuneiform. The last use known of written Sumerian was nearly 2000 years ago. Thanks to its phonetic nature, he use of cuneiform was adapted for many ancient languages, and Akkadian cuneiform was used for diplomatic correspendence. The diplomatic archive of Amenhotep III and his son Akhenaten (18th dyn Egyptian pharaohs) happens to have survived and is made up of cuneiform tablets.
It's true that it took much longer to clean up Sumerian decipherment, that was accomplished by 1944 by the fairly recently deceased Samuel Noah Kramer. He would have finished earlier, but he wasted a lot of time hanging around some coffee shop with his nitwit friends, uh, scratch that. The Sumerians invented the writing system by 3100 BC, by which time Gobekli Tepe had been abandoned for more than 4000 years.
Kramer’s books are fascinating.