In general, we ask that you only post one question at a time, but the answers to these are not particularly long so I will be happy to answer all three of these questions.
- If there are many languages in the Niger-Congo family all in a relatively small area and only a few Indo-European languages all spread out geographically, which area do you think has had more mobile populations? Which area has had people migrating across it and in which area have the people been relatively sedentary? One thing we can infer from this is that there were waves of migration and/or conquest that swept across Eurasia, moving languages far afield and replacing some languages that were previously spoken. By contrast, we can infer that speakers of the Niger-Congo languages have tended to stay in one place and have not conquered one another.
- If people in the Middle East speak languages that are connected to African languages, it stands to reason that they must have had contact with one another. People from Africa must have moved up into the Middle East, bringing their languages with them.
- If you have people who speak a given language surrounded by people who speak a different language, how would that have happened? In the case of the Khoisan, for example, it would seem that either A) the Khoisan speakers penetrated into the middle of the Niger-Congo speakers or B) the Niger-Congo speakers migrated into Khoisan lands and displaced and surrounded the Khoisan. Which seems more plausible to you? Scholars generally believe that the Khoisan speakers and the Nilo-Saharan speakers were engulfed by the people who spoke Niger-Congo languages.