One of the premier ways world power can be understood is to look at the dispersion of languages and language speakers. Nation-states are often synonymous with language groups. The French, German, Dutch, Chinese, and Korean....while other nations are divided by their languages - such as Belgium, Switzerland...
In Africa, there are far more languages than a westerner (particularly the average American!) can fathom. Every tribe - whether they be separated by a few kilometers or live symbiotically with other tribes, typically retain their tribal tongue. Sometimes these languages are spoken by only a few thousand people. Some are not written, and others are in danger of dying out with the elderly, particularly as other regional/national/int'l languages gain in importance.
The Ituri forest has been home to groups of "pygmy" hunter-gatherers for thousands of years. I hate the term pygmy, but there still isn't a better one to use. During the Pleistocene ice age - Bantus expanded from modern Nigeria into the Congo Basin looking for agricultural land and started to live alongside the pygmies. The pygmies have often adopted the languages of their closest Bantu allies, because they depend on them for their basic livelihoods. In fact, the perception that pygmies are completely reliant on the forest is utterly false - they get a slight majority of their caloric intake from the forest, while much comes from their relationship with agriculturalists. Certainly, they still hunt and gather and prefer it very much to agriculture! Their reliance on Bantus, and vice-versa (!) has presumably endured for hundreds and maybe thousands of years. The Bantu languages typically garner more importance than the mother tongue and may lead to a language dying out.
In eastern Congo, Swahili is a bit of a lingua franca that unites a melange of dozens of tribes, but it is not really the mother tongue. For at least the last 500 years, Swahili has evolved as a trad language between African tribes and Arab traders from the Swahili coast of Tanzania/Zanzibar and Kenya. The language can be found inland as far as these traders were able to penetrate - centuries before the Europeans started to penetrate the central African jungles.
The DR Congo was drawn up hastily on a map during the 1885 meeting between European colonial powers, and now has 5 national languages - French, Kikongo, Tshiluba, Lingala follows the Congo river from the Atlantic coast to Kinshasa and 1000 miles upstream to Kisangani, Swahili unites the eastern provinces esp. the cities of Goma, Kisangani and Lubumbashi. Since I've arrived in Congo, I've met several people who speak 4 or 5 languages - typically those who speak English have mastered Lingala, Swahili, French and maybe a tribal mother tongue.
As an American (often synonymous with speaking only one single language), I have struggled to gain a passable level of French since I arrived here. But when I talk with ladies or children in the village, or even try to follow a group of Congolese men sharing a funny story, I am often left marveling at the tones of Swahili but am not really understanding anything!
Many Congolese complain that they are powerless with their colonizing tongue - French. Belgium, left Congo as a Francophone country - and now Congolese cite the effects of colonialism regimes in the disparate levels of development between the Francophone and Anglophone countries in Africa. Their neighbors Zambia, Rwanda, Uganda, Tanzania are all a bit better off than Congo . They hope to eventually add English, as it perceived to be the dominant language-power and it is. If a Congolese speaks English, they can't miss finding a job here. Sure, Google has introduced search engines in many languages, but searching in English will undoubtedly give you the best results if you search for something technical, scientific, or business-related.
So I am left being begged to teach people English while that isn't my job at all. People who typically don't speak French, greet me with it, assuming their inherited colonial tongue is the way to communicate with a white person. I'm also given huge smiles and the source of lots of laughs whenever I attempt the lovely Swahili. It truly is the heart language of everybody here, and in the same way I am so refreshed to speak English when the chances come.