>That just (unintentionally or not) automatically excludes African "voices", thereby turning them into the "other".
African researchers can still publish and read in English, it would be extremely unlikely for the two areas of research to evolve independently. Look at American and Soviet research during the cold war - there was a huge language and political barrier, but the Soviets didn't end up with a unique scientific system.
A lot of things did evolve differently in the USSR. For example in linguistics the Soviet Union widely adopted the strange doctrine of Marrism, only to overturn it later.
During the Stalinist era it was well-nigh impossible to cite contemporaneous publications from non-Communist countries, as it was seen as aiding the bourgeois enemy. (It was more acceptable to cite pre-1917 publications from the West, though.) Even after the Khrushchev Thaw, there was still a policy that researchers cite mainly their compatriots, and cite Western publications only when absolutely necessary.
In some fields of linguistics and archaeology, this did result in the USSR taking a very different course in those disciplines than in the West. In fact, the divide is still palpable today, though now it is no longer a matter of not being allow to cite Western works, rather it is down to 1) the influence of elderly Communist-era faculty who by inertia preserve the old restrictions, and 2) Russian universities being unable to afford Western academic books that can cost into the hundreds of euro.
Another interesting example of Soviet influence on the writings of scientists is Lysenkoism, but I would call that a suspension of biological research, as opposed to a change in biological research.
If the results can be changed by changing the underlying philosophy, then what you're doing isn't science. Science will always arrive at the same results no matter how you choose to metaphysically interpret them or embed them in to your national consciousness. Soviet physics and chemistry tracked their western counterparts very closely and later merged back in without any great surprises. Once the central government released its grip on biology it returned to its natural path, the same path that was being independently followed in the west.
I, like the OP, am referring specifically to African researchers' ability to speak in person at conferences in the West. Africans can and do publish research in English all the time, which is sometimes picked up in "conversation" in the wider global community, but without the social emergent properties inherent in face-to-face communication it's difficult to bring that to wider attention (there's a reason tech companies aggregate in SV, for example).
African researchers can still publish and read in English, it would be extremely unlikely for the two areas of research to evolve independently. Look at American and Soviet research during the cold war - there was a huge language and political barrier, but the Soviets didn't end up with a unique scientific system.