I watch lots of African documentaries and I've realised that so many uneducated people in countries such as Nigeria or Liberia etc can speak English quite well. Sorry if it's a dumb question, I haven't connected the dots quite well yet. (I don't mean countries such as South Africa which I know has English as an official language)
The official language of Nigeria is English. It is a former English colony.
Liberia was founded as a colony for American and Caribbean freed blacks to return to Africa. Its official language is English, and the capitol, Monrovia, is named for American President Monroe.
You can pretty well count that former British colonies will use English, former French colonies will use French, not only for governmental language but often as a source for personal names.