Kanyoro (1991) notes

Kanyoro, M. R. A. (1991). The Politics of the English Language in Kenya and Tanzania. In J. Cheshire, English Around the World: Sociolinguistic Perspectives (pp. 402-419). Cambridge: Cambridge University Press.

Here're some more notes from an academic article on East African English:

Kanyoro says there is definitely a distinct East African English. She also acknowledges that there are differences between the variety spoken in Kenya and that spoken in Tanzania. She attributes this to the differences in the political systems and how each promotes English in the schools. For example, in Kenya, since the time of independence, they have had a capitalist system dependent on foreign investment. In Kenya the schools revolve around students gaining fluency in English and they dedicate many resources to this cause. However, in Tanzania, they have a socialist system that plays up the importance of Kiswahili. In Tanzanian schools English is a secondary subject and the goal is for students to gain proficiency in reading comprehension.