information:extraction
Westermann, Greenberg, and others

Westermann, a pupil of Meinhof, set out to establish the internal classification of the then Sudanic languages. In a 1911 work he established a basic division between 'East' and 'West'. A historical reconstruction of West Sudanic was published in 1927, and in his 1935 'Charakter und Einteilung der Sudansprachen' he conclusively established the relationship between Bantu and West Sudanic.

Joseph Greenberg took Westermann's work as a starting-point for his own classification. In a series of articles published between 1949 and 1954, he argued that Westermann's 'West Sudanic' and Bantu formed a single genetic family, which he named Niger–Congo; that Bantu constituted a subgroup of the Benue–Congo branch; that Adamawa-Eastern, previously not considered to be related, was another member of this family; and that Fula belonged to the West Atlantic languages. Just before these articles were collected in final book form (The Languages of Africa) in 1963, he amended his classification by adding Kordofanian as a branch co-ordinate with Niger–Congo as a whole; consequently, he renamed the family Congo-Kordofanian, later Niger–Kordofanian. Greenberg's work on African languages, though initially greeted with scepticism, became the prevailing view among scholars.

Bennet and Sterk (1977) presented an internal reclassification based on lexicostatistics that laid the foundation for the regrouping in Bendor-Samuel (1989). Kordofanian was presented as one of several primary branches rather than being coordinate to the family as a whole, prompting re-introduction of the term Niger–Congo, which is in current use among linguists. Many classifications continue to place Kordofanian as the most distant branch, but mainly due to negative evidence (fewer lexical correspondences), rather than positive evidence that the other languages form a valid genealogical group. Likewise, Mande is often assumed to be the second-most distant branch based on its lack of the noun-class system prototypical of the Niger–Congo family. Other branches lacking any trace of the noun-class system are Dogon and Ijaw, whereas the Talodi branch of Kordofanian does have cognate noun classes, suggesting that Kordofanian is also not a unitary group.

Pozdniakov (2012) stated: "The hypothesis of kinship between Niger–Congo languages didn't appear as a result of discovery of numerous related forms, for example, in Mande and Adamawa. It appeared as a result of comparison between the Bantu languages, for which the classical comparative method was possible to be applied and which were reliably reconstructed, with other African languages. Niger–Congo does not exist without Bantu. We need to say clearly that if we establish a genetic relationship between a form in Bantu and in Atlantic languages, or between Bantu and Mande, we have all grounds to trace this form back to Niger–Congo. If we establish such a relationship between Mel and Kru or between Mande and Dogon, we don't have enough reason to claim it Niger–Congo. In other words, all Niger–Congo languages are equal, but Bantu languages are "more equal" than the others."

Glottolog (2013) accepts the core with noun-class systems, the Atlantic–Congo languages, apart from the recent inclusion of some of the Kordofanian groups, but not Niger–Congo as a whole. They list the following as separate families: Atlantic–Congo, Mande, Dogon, Ijoid, Lafofa, Katla-Tima, Heiban, Talodi, and Rashad.

Babaev (2013) stated: "The truth here is that almost no attempts in fact have been made to verify Greenberg's Niger–Congo hypothesis. This might seem strange but the path laid by Joseph Greenberg to Proto–Niger–Congo was not followed by much research. Most scholars have focused on individual families or groups, and classifications as well as reconstructions were made on lower levels. Compared with the volume of literature on Atlantic or Mande languages, the list of papers considering the aspects of Niger–Congo reconstruction per se is quite scarce."

Oxford Handbooks Online (2016) has indicated that the continuing reassessment of Niger–Congo's "internal structure is due largely to the preliminary nature of Greenberg's classification, explicitly based as it was on a methodology that doesn't produce proofs for genetic affiliations between languages but rather aims at identifying "likely candidates."...The ongoing descriptive and documentary work on individual languages and their varieties, greatly expanding our knowledge on formerly little-known linguistic regions, is helping to identify clusters and units that allow for the application of the historical-comparative method. Only the reconstruction of lower-level units, instead of "big picture" contributions based on mass comparison, can help to verify (or disprove) our present concept of Niger–Congo as a genetic grouping consisting of Benue–Congo plus Volta–Niger, Kwa, Adamawa plus Gur, Kru, the so-called Kordofanian languages, and probably the language groups traditionally classified as Atlantic."

The coherence of Niger–Congo as a language phylum is supported by Grollemund, et al. (2016), using computational phylogenetic methods. The East/West Volta–Congo division, West/East Benue–Congo division, and North/South Bantoid division are not supported, whereas a Bantoid group consisting of Ekoid, Bendi, Dakoid, Jukunoid, Tivoid, Mambiloid, Beboid, Mamfe, Tikar, Grassfields, and Bantu is supported.

The Automated Similarity Judgment Program (ASJP) also groups many Niger–Congo branches together.

Dimmendaal, Crevels, and Muysken (2020) stated: "Greenberg's hypothesis of Niger–Congo phylum has sometimes been taken as an established fact rather than a hypothesis awaiting further proof, but there have also been attempts to look at his argumentation in more detail. Much of the discussion concerning Niger–Congo after Greenberg's seminal contribution in fact centered around the inclusion or exclusion of specific languages or language groups."

Good (2020) stated: "First proposed by Greenberg (1949), Niger–Congo (NC) has for decades been treated as one of the four major phyla of African languages. The term, as presently used, however, is not without its difficulties. On the one hand, it is employed as a referential label for a group of over 1,500 languages, putting it among the largest commonly cited language groups in the world. On the other hand, the term is also intended to embody a hypothesis of genealogical relationship between the referential NC languages that has not been proven."