The main language spoken by the people of the Kanem-Bornu Empire was Kanuri.

However, the empire used Arabic as the language of administration, diplomacy, scholarship, and religion.

Here’s a breakdown:

• Kanuri (or Kanembu/Old Kanembu): This was the primary language of the majority of the population, especially the ruling Sayfawa dynasty and the Kanembu and Kanuri ethnic groups who were the core of the empire. Old Kanembu was also an important language for Islamic scholarly studies.
• Arabic: As an established Islamic state, Arabic was the language of the elite, the court, and intellectual life. Official documents, correspondence with foreign states, and the records of Islamic law and scholarship were written in Arabic.