How diverse are African languages, and what unites them?

Amidst this incredible linguistic diversity, some widely spoken languages transcend geographical and cultural boundaries, serving as lingua francas and promoting communication and understanding among different communities. Swahili, for example, is spoken by up to 150 million people across East and Central Africa, often as a second or third language. Meanwhile, Arabic has deep historical roots in North Africa and plays a significant role in the religious sphere as the liturgical language of Islam.