No history was reversed. Despite the availability of diffusion, sub-Sahahran Africa never developed a system of writing, built anything but the rudimentary stacking of stones in Zimbabwe and lived an existence equal to Amazonian Indians, Aboriginal Australians and specs of Pacific islands until the colonial period.
The likes of Cortez and Pizarro at least conquered elementary civilizations, no such thing was needed by slave traders.
Ah, no:
In the last two centuries, a large variety of writing systems have been created in Africa (Dalby 1967, 1968, 1969). Some are still in use today, while others have been largely displaced by non-African writing such as the Arabic alphabet and the Latin alphabet. Below are non-Latin and non-Arabic-based writing systems used to write various languages of Africa.
The Bamum (Bamun; also Shumom) system of pictographic writing was invented beginning in the late 19th-century by Sultan Njoya Ibrahim for writing the Bamun language in what is now Cameroon. It is rarely used today, but a fair amount of material written in this script still exists.[6]
Other writing systems developed in West Africa include:
Bassa alphabet[7]
Bété syllabary
The Eghap script was used by the Bagam (Tuchscherer 1999, Rovenchak 2009).[8]
Kpelle syllabary[9]
The N'Ko alphabet.
Loma syllabary[10]
The Mende Ki-ka-ku or KiKaKui syllabary was invented by Kisimi Kamara in Sierra Leone in the early 20th century. It is still used. [11]
The Mandombe alphabet was invented by Wabeladio Payi in 1978 in the Democratic Republic of the Congo. It is apparently promoted by the Kimbanguist Church and used for writing Kikongo, Lingala, Tshiluba, Swahili, and other languages.
N'Ko was invented in 1949 by Solomana Kante in Guinea, primarily for the Manding languages. It is apparently in increasing use in West Africa, including some efforts to adapt it to other languages (Wyrod 2008). [12]
The Vai syllabary was invented by Mɔmɔlu Duwalu Bukɛlɛ for writing the Vai language in what is now Liberia during the early 19th century. It is still used today. [13]
Zaghawa (Beria) was created in 2000 from an earlier proposal made from livestock brands.
The Phoenician alphabet is thought to be the origin of many others, including: Arabic, Greek, and Latin. The Carthaginian dialect is called Punic.[14] Today's Tifinagh is thought by some scholars to be descended from Punic, but this is still under debate.