There is no dominant language in Africa, but if you are traveling in West or Central Africa, French will be the most useful across these nations and regions. Arabic is the dominant language in North Africa, though French is also widely spoken. English is also useful in many countries. Swahili is the most useful language in East Africa. In Ethiopia, most people speak Amharic, which is indigenous to the nation. Even if you know a blanket language like French, it is always a good idea to bring phrasebooks for the native languages. In Senegal, for example, despite being part of Francophone Africa, visitors are likely to find Wolof very useful and sometimes necessary when dealing with residents. The more you wish to interact with locals or go out of the cities, the more important it will be for you to have resources to communicate in the local African language.