The origins of written Swahili demonstrates the historical connection between East Africa, the Arabian peninsula, and the Islamic faith. The Swahili language stems from African roots and is a language of the Bantu branch of Niger Congo. There is, however, a notable Arabic influence in elements of the Swahili written vocabulary, and the earliest Swahili texts were recorded with Arabic script.
The emergence of Swahili language and culture began with pre-Swahili, coastal east-African fishing communities between 100 and 350. The proto-northeast-coastal-Bantu language developed as Bantu
The Swahili coastline is defined as a 3,000-mile-long (4,800-kilometer-long) band of land extending from Mogadishu (Somalia) to Sofala (Mozambique), varying from 32 to 321 miles (20 to 200 kilometers) wide. The Swahili coast also encompasses the islands of Mombassa, Pemba, Zanzibar, Mafia, and Kerimba and the archipelagoes of the Comoros and Lamu. Trade expanded in this area, as Swahili towns increasingly received contact with traders from across the Indian Ocean.
The Arab traders were of particular influence, but other important partners in trade were the Persian, Indian, and Chinese merchants. By 1100, overseas trade occurred frequently, and as trade increased in volume and quality, the Swahili economies benefited with material wealth. Iron trade was prevalent in Swahili towns such as Kilwa, Shanga, and Manda. In addition to material commodities, intellectual ideas were also being exchanged between coastal east Africans and their foreign trade partners. Important among these ideas was Islam and the Arabic language.
Between 1100 and 1300, Islamization intensified within the Swahili community. By the end of this period, Mogadishu was a center of Islamic learning with three mosques. Wealthy Swahili merchants incorporated trends they observed among the more affluent Arab merchants by integrating clothing, furniture, designs, and, most important, an Islamic education for children. It is in the era of increased Muslim conversion around 1100 that Swahili began to be captured in written Arabic script.
Because the Swahili communities incorporated elements of Islamic law into their judicial practice and religion in their belief systems, there was an increasing need to be able to read Arabic script to observe religious rights and privileges. In addition, because trade had become so intense in volume since the eighth century, there was a greater need to keep written financial records. Rather than learning both the script and language of Arabic, some enterprising Swahilis sought to use the script to capture their own language. Thus, Swahili was documented with Arabic script. It is clear from scholarly research that these Arabic-script Swahili documents could not be read by literate Arab speakers unless they knew the Swahili language.
As Islam became more widely followed among the Swahili, the incentive for a written form of Swahili grew. Wealthy and devout African Muslims learned how to read and write in Arabic. Swahili remained the language of daily discourse while Arabic increasingly became the language for religion and often legal correspondence. However, this was not the case for all Swahili, and some people relied instead on Swahili-language Arabic script. The advent of Swahili script led to the flourishing of original Swahili literature and poetry in written form.
Arabic-script Swahili writings are important sources of historical information about medieval Swahili history. While much of the writing was devoted to poetry, literature, and religious subjects, the events of everyday life are captured in the writings as well. From these documents, it is clear that Islam and Arabic culture had a significant, lasting influence on the Swahili.