asymmetry of the oscillation causes the bed forms to shift laterally at non-negligible rates. I will unofficially term cross stratification of this kind climbing-bed-forms cross stratification. Bed forms are said to climb when there is overall aggradation of the sediment bed while the bed forms are moving; see a later section for details.) 502
Swahili is the most spoken language in Africa, with over 100 million speakers. It is a Bantu language believed to have originated from other languages, mainly Arabic, due to historical interactions between Arabs from the Middle East and East Africans.
Languages of Africa: about thousand languages classified in four major language families: Afro-Asiatic (e.g. Berber language), Nilo-Saharan, Niger-Congo (Bantu), and Khoi-San.