How did the Swahili language affect trade in the East African city-states?

The Swahili language was a language that was actually very well in connecting people from different places, and it was a language that enabled communication between lots of people from different backgrounds. The Swahili language is actually a language that has its basis in the Bantu, but over time, because of the constant communication with lots of people that came in this part of Africa to trade, the language incorporated lots of words and phrases from other languages, so it became a mixed language that lots of people started using for mutual communication.