People have often wondered how the Incas could have built such a complex civilization without writing anything down. Maybe they did write it down:
The Incas may not have bequeathed any written records, but they did have colourful knotted cords. Each of these devices was called a khipu (pronounced key-poo). We know these intricate cords to be an abacus-like system for recording numbers. However, there have also been teasing hints that they might encode long-lost stories, myths and songs too.
In a century of study, no one has managed to make these knots talk. But recent breakthroughs have begun to unpick this tangled mystery of the Andes, revealing the first signs of phonetic symbolism within the strands. Now two anthropologists are closing in on the Inca equivalent of the Rosetta stone. Daniel Cossins, “We thought the Incas couldn’t write. These knots change everything” at New Scientist (paywall)
It makes sense that if people recorded numbers, they would also record words. Numbers are not self-explanatory. Are there known contrary instances?
See also: Were humans in North America 130,000 years ago? Some evidence considered. SAPIENS discusses the “chipped rocks, crushed mastodon bones, and reliable dates showing the remains are 130,000 years old”