Answer :
Final answer:
Swahili served as a lingua franca in East African trading ports, showcasing the cosmopolitan nature of African port cities and their role in facilitating trade.
Explanation:
Swahili became the common language in trading ports along the East African coast during the Middle Ages, serving as a lingua franca among merchants from different cultures. This indicates that African port cities were cosmopolitan hubs facilitating trade exchanges, incorporating influences from Arabic, Hindi, and European languages into the Swahili language.
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