Analysis of information sources in references of the Wikipedia article "Niger–Congo languages" in English language version.
The term [Niger–Congo], 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 (p.139)