While the Wookiees were enslaved by the Galactic Empire, the Wookiee resistance used Xaczik as a secret language to pass messages along. Since the Humans of the Empire thought all Wookiees were alike, they never realized that the Wookiees spoke languages other than Shyriiwook. Thanks to Imperial ignorance, Xaczik became an unbreakable code.
- The Essential Guide to Alien Species
- The Official Star Wars Fact File 12 (WOO2, Wookiees)
- The Official Star Wars Fact File 42 (KAS1, Kashyyyk)
- Galactic Phrase Book & Travel Guide
- The Complete Star Wars Encyclopedia