If your tradition would allow CG, writing a book may be a worthwhile endeavor!
When i was in college, my linguistics professor was working on a project to document the Zuni, Aztec, and Laguna tribe languages in the SW. The reason for this was because cumulatively, those three tribes (at the time) had less than 500 native speakers left, and the language was going to be lost to time. When a language dies, traditions and culture die with it. However, the biggest complication she had was these languages were never written languages, they were entirely verbal so they had no writing system, which meant there were no grammar definitions for written word. Talk about making the process incredibly complicated! Another complication was there is a cultural disposition against photography of tribal members and writing of the language due to the belief that recording such things in such permanent form takes from the spirit, removing the life from it.
I digress. If you're able, I'm sure even if you're the last one to care about the old ways, many of us would buy a book describing those ways!