DAKAR, Senegal—Makhtar Fall sat behind his anchorman's desk in a two-button blazer, clutched a stack of cue cards and then cleared his throat to report the evening news.

"Bienvenue, we've got news for you!" he rapped in French. A menacing electro-beat blared in the background as Mr. Fall chopped his hands through the air the way rappers do. "We've got some good news, some bad news, but we've got some news for you!"

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