""Dialects form when groups of people who speak the same language move apart, and their languages change in different ways. At first, each group can understand the variants spoken by the other groups, but after hundreds of years of separation the variants may become mutually unintelligible. By that time, distinct languages have formed with cognates and similar grammatical systems. Swahili, for example, belongs to the Bantu language group. All Bantu languages trace their roots to Cameroon and western Nigeria, where linguists believe the ancestral language originated."" [url][/url]http://autocww.colorado.edu/~toldy3/E64ContentFiles/LinguisticsAndLanguages/AfricanLanguages.html I quoted the above paragraph from the URL i pasted here... Its a good source of info on language culture mix in africa...Bantu languages do trace their roots to western nigeria as well as eastern nigeria as if nigeria is in the root area of the oldest known language group