How did Chad get their Arabic language?

Chad's official languages are Arabic and French. Arabic is not the predominant language spoken in Chad; that would be Chadian Arabic, a group of closely related Arabic dialects. It serves as the lingua franca between native language speakers as well as the national and the international language (for matters requiring a language other than French). Most of the urban and educated Chadians are speakers of Chadian Arabic.

The Arabic language arrived in Chad with Muslim nomads and traders coming down from Northern Africa over a thousand years ago and through its subsequent domination throughout the Sahel.