Why does every African movie character have the same accent?

Will Smith in Concussion

Hollywood has an Africa problem. The latest manifestation of this is the trailer of Will Smith’s new film, Concussion, in which Smith plays the real-life Nigerian pathologist Dr. Bennet Omalu.
In 2002, Omalu discovered that the hard hits US football players receive in the National Football League (NFL) may cause serious brain damage. His revelations, published in a 2005 paper in the journal Neurosurgery, threatened to kill the game. As the 2013 Frontline documentary “League of Denial” shows, Omalu faced significant pressure to stay quiet about his findings.
Omalu is a hero, and choosing him as the subject of a feature film makes perfect sense. But the execution has been less than perfect.
Following Concussion’s trailer’s release on Aug. 31, it did not take long for people to notice that the Fresh Prince’s accent did not exactly sound Nigerian. Africa is a continent of 54 countries, with an estimated 2,000 languages spoken, all characterized by different patterns of speech. But Smith’s fake accent is a generic lilt, sort of suggestive of how some Africans speak, but with nothing specifying “Nigerian” in the way that, say, Hollywood actors carefully distinguish between Italian and French accents in English.
This is not the first time that an American actor has struggled to authentically portray an African. Remember Morgan Freeman playing Nelson Mandela in Invictus? Again, sounding like a rather generic African speaking.
 Read it on QUARTZ AFRICA