Berber languages suggests that the C-Group population — which, along with the Kerma culture, inhabited the Nile valley immediately before the arrival of the first Nubian speakers — spoke Afro-Asiatic languages. Roger Blench (2018) suggests that Proto-Berber speakers had spread from the Nile River valley to North Africa 4,000-5,000 years ago due to the spread of pastoralism, and experienced intense language leveling about 2,000 years ago as the Roman Empire was expanding in North Africa. Hence, although Berber had split off from Afroasiatic several thousand years ago, Proto-Berber itself can only be reconstructed to a period as late as 200 A.D. Blench
Northern Berber languages fall into three groups: The eastern boundaries of the North Berber varieties are uncertain. Some linguists include the Nafusi and Ghadames languages, while others do not. Most regard Ghadamès as lying outside of Northern Berber, but the "Ethnologue" does not. There is no authoritative answer as to whether the Northern Berber varieties constitute a language rather than a dialect. Some academics believe that not only Northern Berber but all the Berber languages are dialects of a single language, whereas others come up with much higher counts. At any rate, mutual comprehensibility among the Northern Berber varieties is high, though not