A Cherokee man named Sequoyah ended up serving as a soldier in one of the early conflicts between English settlers and other Native American groups. In this case, his people were on the side of English settlers against rival tribes (see [2]), so he was serving alongside English soldiers in the conflict. He saw them reading and writing - something he couldn't do, since the Cherokee language had no written script at the time - and went "wait this seems like it would be pretty useful".
So Sequoyah, who until this point had never encountered a writing system, decides he's going to make one. He starts by trying to create a symbol for every word, but decides that's too difficult, so he switches to symbols for syllables instead. It took him ten years to finish it, but once he did, it was adopted by nearly every speaker of Cherokee within only a few years. It's still the primary writing system for the Cherokee language today.