In linguistic and history when a group of people share the same linguistic phylum, it means that at one time their ancestors were once part of the same population (beside in cases of language shift). For example, all Niger-congo speakers were at one time, in one location and all were speaking a language we can call proto-Niger-Congo. Same thing for proto-Mande-Congo people. All proto-Mande-Congo descendant languages (Igbo, Yoruba, Wolof, Fulani, Mande, Bantu, Kongo, etc) are all descended from the same population who were once speaking a language we can call proto-Mande-Congo. In linguistic, we say those languages have a genetic relationship between one another. See below:



This was taken from the book:


In the book, you can also read about the Niger-Congo people history:

The first expansion of Niger-Congo peoples appears to have stretched from as far east as the Nuba Mountains of Sudan, where proto-Kordofanian would have been spoken, to as far west as Mali, anciently the territory of the Mande and Atlantic-Congo branches. Just how long ago this period of expansion took place remains unknown.

Basically, here it says the Niger-Congo speakers (also called Niger-Kordofanian) had their origin in the far east around the Nuba Mountains in Sudan (Kordofan region) and that they then spread to as far west as Mali in West Africa for their first expansion. It can also be noted that the E-M2 (E1b1a) haplogroup also is said to have its origin in the same approximate region. An haplogroup widespread among Niger-Congo speakers along with other haplogroups.

So basically, Niger-Congo speakers all have the major part of their origin from Sudan at a time probably preceding the Green Sahara period (with the northward shift of monsoon rains for many century). The Green Sahara period could relate to the period of expansion of Niger-Congo speakers toward the then green sahara to eventually reach Mali in West Africa.

Niger-congo speakers could also be behind the development of pottery in West Africa, since the earliest date for ceramic in Africa is from Ounjougou in Mali. It is mentionned in the book History and the Testimony of Language (2011):

The ceramic technology of these peoples directs the attention of historians to a very important story for world history—namely, the global primacy of sub-Saharan Africans in the invention of ceramic technology. Pottery making was already a fully established and not at all incipient technology in the archaeology of the southern half of the eastern Sahara by 8500 BCE, as early as the claimed dates for pottery in Japan. But Saharan pottery making was not even the first ceramic technology in Africa. The earliest known pottery in all of human history comes from West Africa, from the modern-day country of Mali, and dates to the centuries 10,000–9500 BCE. The archaeology of the makers of this pottery belongs to the West African Micro-lithic Complex,39 a set of archaeological traditions everywhere associated with peoples speaking languages of a third African family, Niger-Congo. For historians the question still to be answered is, did ceramic technology among nilo-saharan speakers in the eastern and other parts of the sahara diffuse to them a thousand or more years later from far-away West Africa, or were these two separate and independent African developments of this key early technology?

Then from the same book African Languages: An Introduction (Nurse 2000) from above:

A second, but still early and important stage in Niger-Congo history was the proto-Mande-Congo era. At this period, or so it appears from the evidence of word histories, the cultivation of Guinea Yam and possibly other crops, such as the oil palm, began among at least the peoples of the Atlantic and Ijo-Congo branches of the family (Williamson 1993 proposes the early words for these crops; Greenberg 1964 identifies an Atlantic and Ijo-Congo verb for cultivation,*-lim-). Between possibly about 8000 and 6000 BC, these peoples spread across the woodland savannas of West Africa, the natural environment of the Guinea yams. At that time, woodland savanna environments extended several hundred kilometers farther north into the Sudan belt than they do today. (Edit:Green Sahara period)

Here it posit that Ancient Niger-Congo speakers may have expanded demographically and geographically in West Africa while bringing with them yams and other crops cultivation(palm tree, raffia palm tree, black-eyes peas and voandzeia) while domesticating the guineafowl (among other things).

Before their migration in West Africa from the north . West Africa was probably inhabited by small groups of hunters gatherers. Almost no traces of previous population in West Africa exist beside maybe remnant in the the Jalaa and Laal languages. We can also note the A00 haplogroup found recently among African-American and West African people. The first group to split from the rest of the human populations (and vice versa, that is the other humans are the first group to split from them). Which could also be some remnant of previous hunter gatherers populations in West Africa.

In this book:


It describes the situation before the migration of Niger-Congo speakers in West Africa this way:

For whatever reason, West Africa was only populated extremely sparsely until the end of the Pleistocene, some 12,000 years ago (Muzzolini 1993).

Adding:

One feature of the Niger-Congo region is the virtual absence of residual languages. What languages the MSA hunter-gatherers spoke must remain unknown. Only in Southern Africa, where the expanding Bantu-speakers encountered the Khoesan, does a real mosaic of farmers and hunter-gatherers still exist. But within much of the core Niger-Congo area, only Jalaa in Nigeria and Laal in Chad (see Table 8.1 and Map 8.1) seem to be true remnants of an earlier diversity that must have characterised the continent. These fragments both hint at a more ancient stratum of hunting-gathering populations in West Africa, present at the time of the Niger-Congo expansion but almost completely absorbed by them. Niger-Congo must have expanded and assimilated all the resident groups and must therefore have had highly convincing technological or societal tools to bring this about.

Then we got a more precision from this book:

Agricultural Invention: West African Planting Agriculture, 9000-5500 BCE

To the south of the Sahara, African peoples found other innovative ways to respond to climatic shifts that emerged by 11,000 BCE. None of these at first entailed the adoption of agriculture but were instead approaches that enhanced the productivity of the wild environment.

In West Africa a variety of consequences was set in motion by the increased rainfall between 11,500 and 8000 BCE. All across a 300- to 400-kilometer-side zone extending inland from the Atlantic coast, from Senegambia in the west to Cameroon in the east, woodland savanna was replaced by expanding rainforests. In Cameroon the spread of the West African forest zone connected up with the newly expanding equatorial rainforest of central Africa. The woodland savanna belt shifted nortward into the previously open savanna areas of the southern Djouf Basin. In addition, stream flow increased, and more rivers than before ran year round.

The shift to still wetter climate in West Africa during and after the ninth millennium BCE had different effects in different areas. Increased river flow enhanced the possibilities for fishing, and the nortward advance of woodland savanna opened up new areas favorable to yams. At the same time, however, many areas nearer the coast that were previously covered by moist woodland savanna began to be swallowed up by the expanding rainforest, in which there was too little direct sunlight to support the particular yam species favored by the Niger-Congo peoples.

But it was also the period in West African history in which a new African agriculture was invented. We do not know yet when some of the Niger-Congo communities commenced the shift to deliberate cultivation of yams, not exactly where. The most probably answer is that the changeover began sometime around 8000 BCE and that the locales of the first yam agriculture lay in the intermediate parts of the West African woodland savana zone -in areas where the abundance of wild yams had declined with the spread of woodland conditions, but where a farmer's efforts in preparing the ground and planting and protecting the growing plants could effectivly reverse that decline.

We can this new and independent invention "West African planting agriculture," from the fact that the farmers reproduced their staple (most important) crops, the different types of West African yam, not by sowing seed, but by planting a part of the yam itself back in the ground. These early West African farmers by no means restricted their agricultural experimentation, however, to just yams. They domesticated one animal, the guineafowl, at probably an early stage in their development of food production. From an early period they also tended to two tree crops, the oil palm and the raffia palm. The oil palm provided cooking oil for its nuts as well as palm wine from its sap; the raffia palm was another source of palm wine, and by the fourth or third millennium BCE its fibers and become highly valued by West Africans for the weaving of raffia cloth. In the woodland savannas of modern-day Nigeria and Cameroon. Niger-Congo communities brought under cultivation two major food plants grown from seed, black-eyes peas and voandzeia (and African groundnut), probably as early as the sixth and fifth millennia. Okra was still another quite early crop of Niger-Congo farmers, while the kola nut, a tree crop of the West African rainforest, became important later, in the last 3000 years BCE. The inventors of this agriculture, by the way, were women, who in pre-agricultural eras and borne the chief responsibility for collecting of wild yams and other wild plant foods.

Gradually an important new development in technology took hold along with the new economy. Niger-Congo peoples began to make polished stone axes, in this way becoming able to effectively clear patches of woodlands and grow their sunlight-requiring yams and oil palms in more and more areas.

Great post here.
Two of my previous post dealing with this era my also be of interest.



When the Arabian peninsula was Northeast Africa
https://www.nairaland.com/1530367/when-arabian-peninsula-northeast-africa

An Account Of The Dispersal Of People Across The Sahale
https://www.nairaland.com/1519253/account-dispersal-people-across-sahale

Great post by the gods bearer. I know say one day our history will echo our fine historical traditions, then we will meet all the Pot manufacturers whose terracotta glass and bead ceramic company west Africa, reg. 1000 B.C. shape west African history. Except the pots were old sacred objects brought from somewhere, or the artifacts were indeed our ancestors. even so, they left behind worthwhile info for us in different cryptic forms.

The following quotes are from the book: The Oxford Handbook of African Archaeology edited by Peter Mitchell, Paul Lane (2013)

Basically, it tells us people now living in West Africa (Akan, Igbo, Yoruba, etc) come from the Sahara during its desertification. (and before this migrants from eastern Africa considering the origin of Y-DNA haplogroups E-P2 and the linguistic origin of Niger-Congo(-Kordofanian) languages).

[img]http://image.bokus.com/images2/9780199569885_200[/img]

In West Africa, there is very little evidence for people south of the Sahara prior to the mid-Holocene, and such evidence as does exist is primarily of small scattered groups of mobile hunter-gatherers, some of whom returned frequently, possibly even seasonally, to the same places.

Davies(1967) and Shaw (1978) both argued that before the desiccation of the Sahara, not only were Saharan inhabitants not compelled to move southward, but it was virtually impossible for them to do so. Postulated barriers to human occupation in southern West Africa include the difficulty of making a living in the dense rainforest prior to the advent of iron tools, and potentially lethal diseases such as malaria, onchocerciasis, and trypanosomiasis, the latter an added problem to herders because it can be devastating to cattle (Smith 1992). Only when climate zones contracted could people, and especially herders, move south.

The artefacts found at many early sites support a northern origin for SMA people in southern West Africa. Projectile points are often in a 'Saharan Style' with concave or convex bases, and pottery often bears comb and roulette impressions very similar to types known from the Sahara and the Nile Valley as early as the tenth millennium B.P.

It's written clearly. People in southern West Africa (Yoruba, Igbo, African-Americans, etc) have a northern origin. A green Saharan origins. They brought with them archaeological artefacts from the Green Sahara period including pottery and else.

yes that true.