Taken from: Youssouf KamaltomIIIfasc2
Full name: Abu'l Faraj Muhammad ibn Yusuf ibn Abi Ya'qub Ibn an-Nadim
He mentions the Nubians, Abyssinians, Beja, different varieties of the Zanj, the Al-Marawa, the al-Astan.
Notice about the Soudan; as to the people of the Soudan like the Nuba the Boudja the Zaghawa the Marawa the Istan the Barbar and the different kinds of Zandj –with the exception of Hind , who write in Hindi language to understand each other – they do not have a known written language nor written literature. Only al Djahiz in his kitab al Bayan says that among the Zandj one can find a kind of rhetorique and eloquence that is their own and in their own language. Somebody who had witnessed this said: When they are in a difficult situation like war, an orator from among them sits down on a higher place, puts his eyes down and starts talking in a language that resembles a murmur, which is understandable for the others; the same informer continues: as a result of this a decision is made among them on how to react, and accordingly they go to action, but God knows best.
Al Jahiz was a client (mawla) of the Banu-Kinana, and his grandfather was black.
Note; this is also found in Al-Khatib; Ta'rikh vol XII