The English term "goodbye" matches the Swahili term "kwa heri, kwa herini"

Arab Influences
Arabic has played a significant role in both influencing Swahili as well as helping to develop it. Arabic’s role in the language goes back to the interactions and influence Arabic traders had with people who lived on the eastern coast of Africa. As a result, Swahili eventually became the language spoken in that part of Africa. In fact, it became the standard language for Bantu tribes who spoke many other languages starting in the 19th century.
Moving Inland
Also around the 19th century, Swahili started to move inland from the eastern coast of Africa because Arab ivory traders and slave traders used it as the primary mode of communication. They went all the way to the Congo and north to Uganda, which helped spread the language.
A Common Language
During the colonization of Africa, Europeans decided to adopt Swahili and not force people to learn their languages. This was both true of the British and the Germans who encouraged its use in schools, the military, and government.