Azhar was a secret language used by the Sorceresses of Rossak before the Butlerian Jihad. Zufa Cenva kept a thick notebook in this undecipherable language. It was inherited to the Bene Gesserit and was the language of the Azhar Book. To keep her writings secret from her husband, Padishah Emperor Shaddam IV, the Bene Gesserit Lady Anirul Corrino kept a journal in the impenetrable code language of the Bene Gesserit, the long-forgotten tongue used in the ancient Azhar Book.