The Telling by Ursula K. Le Guin
There have been eighty requests to send an Observer into the hinterlands of the planet Aka to study the natives. Much to everyone's surprise, the eighty-first request is granted, and Observer Sutty is sent upriver to Okzat-Ozkat, a small city in the foothills of Rangma, to talk to the remnants in hiding of a cult practising a banned religion. On Aka, everything that was written in the old scripts has been destroyed; modern aural literature is all written to Corporation specifications. The Corporation expects Sutty to report back so the non-standardised folk stories and songs can be wiped out and the people 're-educated'. But Sutty herself is in for an education she never imagined.