Nahuatl

The Qari speak Nahuatl, and communicate not in written language but in a form of knot-tying and rope work called Khipu. While they do have pictographs, these are largely used as decoration and have a more religious or symbolic purpose rather than for communication.

Nahuatl can be transcribed by using the common alphabet, however, spelling discrepancies are very common due to most transcribers writing things down phonetically.

Khipu is notoriously difficult to learn, but it has the incredible advantage of being readable in the dark. Or underwater.