Ogean

Ogean is the native language of the Ojiongo.
Ogean is not exactly a secret language, but Ojiongo are generally fairly reluctant to teach it to outsiders. Even with a willing teacher, Ojiongo is grammatically complex.
Ogean has the only Scaraquan system of writing that is not a derivative of Asta'lash script. Where Asta'lash's alphabet is based on phonemes and sounds, written Ogean involves many pictograms and has hundreds of different letters.