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.
Africa is second largest and second most populous continent in the world with a total population of 1.111 billion. African languages belong to one of the four language families: Afroasiatic, Nilo-Saharan, Niger-Congo and Khoisan. Around 2,000 languages are spoken in Africa.