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.
The principle languages on the continent include Arabic, French and English. Arabic was ranked the 5th most spoken language in the world by research group Ethnologue, with over 240 million speakers worldwide. In Africa, there are more than 100 million speakers, with Egypt accounting for more than 54 million.