As the Umayyad dynasty expanded their control of North Africa and the Liberian peninsula, the Arabic language also spread. What was one reason for the spread of Arabic along with the spread of Islam?

Written language were already being used in those areas.
The sacred text of Islam, the Koran, was written in Arabic
People in those areas did not have their own written languages

All of the above reasons contributed to the spread of Arabic along with the spread of Islam. The use of written languages in North Africa and the Arabian Peninsula prior to the Umayyad expansion facilitated the adoption of Arabic as a written language. Additionally, the fact that the sacred text of Islam, the Quran, was written in Arabic made Arabic a revered language for Muslims and encouraged its learning and usage. Finally, many people in those areas did not have their own written languages, which made Arabic an attractive option for written communication and administration.