Wikipedia Reference Information
Pravic is a fictional language used and referred to in the science-fiction book The Dispossessed, by Ursula K. Le Guin. Pravic is a fictional constructed language: in the book, it is said to have been constructed by a person named Farigv. Pravic is spoken on the planet Anarres, where followers of the philosopher Laia Asieo Odo chose to be exiled in order to achieve the goal of a functioning anarchic society. Anarres is actually the semi-desertic moon of Odo's homeworld Urras. As far as we know, the only language spoken widely in Anarres is Pravic, though the few people that have contact with Urras (mostly trade officials and scientists) also speak Iotic, the language of Urras's dominant nation A-lo.
The complete, up-to-date and editable article about Pravic can be found at Wikipedia: Pravic