Many African nations have European officials language due to past

Establishment of colonies.

Explanation:

During the colonization, European countries forced the locals to learn their language. The European countries believed that it will be easier for them to control and coerce the locals if they understand their language.  (some European countries such as Spain even force the locals to abandon their religion to adopt Christianity on top of the language)

The colonization's in Africa occurred for almost 100 years. So, several African generations were born and required to learn European language since early age. As a result, many of the countries still use European official language even after the colonization was done.

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