Out of Africa hypothesis[edit source]
According to the proponents of this theory, Syria and Mesopotamia was originally inhabited by a non-Semitic population as the earlier linguistic tradition of those areas can be seen from the non-Semitic toponyms preserved in Akkadian and Palaeosyrian languages. The African origin may be firmly confirmed with the relationship between Afro-Asiatic and the Niger–Congo languages, whose urheimat probably lies in Nigeria-Cameroon. It appears that the most numerous isoglosses and lexicostatistical convergences link proto-Semitic to Libyco-Berber. Evidently, proto-Semitic speakers were still living in the Neolithic Subpluvial in the 5th millennium BC when the Sahara was much wetter, retaining a link with Berber long after other Egyptic andProto-Chadic separated.
Rock drawing attest to vibrant Neolithic culture in the Sahara that collapsed due to desertification and climate change ca. 3500 BC, forcing the Proto-Semites to emigrate en masse through the Nile Delta to western Asia. They were probably responsible for the collapsing of the Ghassulian culture in Palestine around 3300 BC. Another indication to the arrival of the proto-Semitic culture is the appearance of tumuli in 4th and 3rd millennium Palestine, which were typical characteristic of Neolithic North Africa. It is possible that at this point, the ancestors of the speakers of Elamite moved towards Iran, although the inclusion of Elamite in Afroasiatic is only contemplated by a tiny minority. The earliest wave of Semitic speakers were theAkkadians, who entered the fertile crescent via Palestine and Syria and eventually founded the first Semitic empire at Kish. Their relatives, theAmorites, followed them and settled Syria before 2500 BC. The collapse of the Bronze Age culture in Palestine led the Southern Semites southwards, where they reached the highlands of Yemen after 2000 BC. Those crossed back to the Horn of Africa between 1500–500 BC.