By my calculations, there are five dominant languages spoken in Africa, and I speak four of them. English, due to its international appeal, is the first and most commonly spoken language. It is dominant in the South. I would guess the second language to be Arabic, dominant in the north, followed closely by French, which is dominant in the West. In fourth is Swahili, which is spoken in East Africa. In Kenya and Tanzania Swahili is the lingua franca, while it is a second language in Uganda, the DRC, Rwanda, Burundi and Northern Mozambique.
Rounding out the top five, is the only language I'm not comfortable speaking. Portuguese, which is spoken in Mozambique and Angola. Although I began studying Portuguese in Mozambique, I had to leave the country before I had any real grasp of the language.
Arabic, meanwhile, has numerous different dialects. I can converse in Egyptian, Lebanese, and Moroccan Arabic. Egyptian is the most widely understood.