Ask a Moroccan what language they speak at home and the answer may not be "Arabic" — it may be al-darija. The names Arabic speakers use for their own language are not interchangeable. Each one is a small daily act of self-positioning inside the language.

A learner can spend two years on Arabic and still be lost in a Cairo café. There is a category of Arabic that fills nearly every conversation and that almost no textbook teaches — the connective tissue, the greeting rituals, the religious-cultural phrases that carry the language.