Language and Unitongue

Every person on Opeira has the ability to speak the common tongue of the world. This language has many names across cultures, but is known to most as "unitongue." Other names include "The Host's tongue" and "god's language."
The Host's tongue was indeed taught by the Host, that god of universal, undiscriminating hospitality and brotherhood. He insisted that every man that walked the earth be able to communicate with each other, and taught every person his own tongue without regard for their race. As a result, Unitongue is a worldwide language, one taught by all cultures and races to their children.
Other than this common tongue, 8 other languages exist on Petra, one for each tempered race. The knowledge of these languages are exclusive to the respective race. Tempers do not teach those not of their kind their language. Of course, on occasion it happens regardless, but racial tongues are considered a sacred thing that only those carrying the right blood may know and speak.
Not all tempers know their racial tongue. Those who grow up in communities of their own kind are guaranteed to know it, but whose who were raised among many different kinds of people may not have had the opportunity to learn. Tempered communities tend to speak their racial tongue amongst themselves, only switching to Uni if they need to communicate with someone not of their kind.
Humans are only familiar with the Host's tongue. Tempers are generally bilingual.