The Jankenjin are a race "divided by a common language". In theory, our people have one language, Jankengo, however, Jankengo is divided up into dozens of different dialects, most of which are mutually intelligible. Usually.
Our language is based on Kamurigo, a long-dead language once spoken in the city-state of Kamuri on our Southern Continent. In ancient times, the great Jankenjin leader Sumugu the Conqueror transformed Kamuri from a middle-sized city-state to the capital of a world-spanning empire, a feat known as the First Unification of the Jankenjin. Kamurigo was originally the official language of the Kamuri Empire, but it quickly turned into a sort of pidgin tongue, absorbing the languages of the various conquered states. This new, hybrid language became what we call Classical Jankengo.
With the fall of the Kamuri Empire and its breakup into hundreds of small petty nations, Classical Jankengo became corrupted as local, dialectic versions of the language evolved, resulting in the linguistic mess we have today. (The process is somewhat like what happened to Arabic following the Muslim conquest. The classical Arabic spoken by the followers of Mohammed broke up into regional dialects, so that the "Arabic" spoken in, for example, Morocco is barely understood by a speaker of the "Arabic" spoken in Iraq.)
Today Classical Jankengo in its "pure form" is only used as a liturgical language of the Northern and Southern Orthodox Zaakuwando churches. The Scrolls of Zaakuwan and The Scrolls of the Followers are all written in Classical Jankengo, though most Jankenjin are familiar with them only in dialectic translations. The various provinces of the Triune Republic and its neighboring Free States each speak their own dialect. There's no one dialect that's considered by the Triune Republic government to be the "national language", so all public materials tend to be printed up in multi-dialect versions, usually the local dialect plus three or four nearby ones.
Now, after all that--language education. Outside of the occasional religious school, Jankenjin schools teach in the local dialect. Additional dialects are taught as part of our language education program, and it's expected for most Jankenjin to be fluent in more than one. Mastery of multiple dialects is considered a sign of a well-educated Jankenjin, especially for one who may have political ambitions.
