Did American Indian cultures had no written language until the early 1800s?

Answer 1

In the area that is the US and Canada there was not exactly. There was a system to record symbols for memory aids. In Mexico there was.

In the Northeast, in New England, Mid Atlantic, Great Lakes and Canada, the native people (mainly the Haudenosaunee) used strings of shell beads arranged in belts called wampum as a type of record keeping. The designs and colors made a code that was used as a memory aid. They recorded treaties, laws, religious ceremonies, certificates of authority, historic events, story telling and other things. They could be fluently "read" by those who knew how. They are read right to left like Arabic or Hebrew. They were not used as currency by the Haudenosaunee. That came late when the colonists had a shortage of metal coins.

It is often forgotten that geographically North America includes Mexico. There were several writing systems there. They are: Aztec, Mixtec, Olmec, Zapotec, Mayan, Isthmian or Epi-Olmec, Mixe-Zoquean.

Answer 2

False. Olmec writing dates back to about 3000 years, and there were many other writing systems as well.