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.
Official Language: Portuguese. Portuguese is spoken as a first or second language by just over 70% of the population. There are approximately 38 African languages in Angola, including Umbundu, Kikongo and Chokwe. Benin. There are 55 languages in Benin, the most popular of which are Fon and Yoruba (in the south) and Beriba and Dendi (in the north).