Also, while there are many languages in Africa, the number of coherent families isn't necessarily that large. For example, Bambara is part of a larger family of

Also, while there are many languages in Africa, the number of coherent families isn't necessarily that large. For example, Bambara is part of a larger family of languages that are more like highly-divergent dialects (or so I'm given to understand -- I was lucky to communicate at all in my broken Bambara and pidgin French). By the same token, Arabic has a multitude of spoken dialects that are barely intelligible to each other. I also think that the question suffers by failing to compare the range of languages found in other regions. The geographic distribution of the Indo-European language facility is comparable to Africa and contains around 500 known languages, though it is likely that at least as many were extinguished through various means (peaceful and not) over the centuries. Linguistic diversity is the norm, not the exception, though large-scale political consolidation tends to mask this.