Languages as a symbol for opportunity
Because of language, Isabelle Eberhardt is able to travel broadly. As long as she can find someone who speaks one of the many languages she can speak, she can go anywhere. But her opportunity is limited by gender, so language symbolizes her intelligence (because popular belief in her community is that women are stupid), and her ability to tell stories leads her to design a male character to fool people all across North Africa into believing that she was a man.
The Quran as symbol
The Quran represents itself, but in Eberhardt's relationship to God, the Quran represents the center of authority, because she knows from the duplicity in her culture that the version of religion she sees in her culture might be a deficient picture of what the Quran might really be saying. She never leaves the Quran or her Muslim faith, but she considers herself free to believe what the book tells her, without reference for the men who would bind her in their gendered, hypocritical rules.
Drugs and alcohol
Fun is symbolized by altered states of consciousness, which Eberhardt gravitates toward. She gets to experiment and party, even though it is under false pretenses about her gender. She gets to do fun things that normal rule-following girls in her community could never dream of. There are problems with this indulgence, like the cost on the physical body of Eberhardt.
The desert as symbol
The desert is the domain of solitude. It symbolizes Eberhardt's existential solitude, because no one can tell her what to think or believe anymore. Her very travel is an indication of that, and she is a desert nomad truly. She finds herself most free by wandering, by finding life in all its flavors as she goes along. She is skilled at obtained good experiences, and the desert represents the solitude caused by that endeavor.
Sexuality and freedom
There is a clear symbolic demonstration of freedom. She shamelessly engages in sex with secret partners, letting them in on the ruse that she isn't a man. She loves the sex, and she has fun with the role confusion, so why feel bad about things? That doesn't settle squarely with her religious views, so in her experience of Islam, she would be considered an absolute heretic by some, and a true mystic by others—a prophet of freedom and shamelessness.
