How distinct are any written conventions, dialectic terminology, etc in the country?

Sheng is one distinct variant of Kenyan english, B-Y.

The young urban people in Nairobi speak a peculiar dialect, a mixture of English, Swahili and some ethnic tongues, which is known as Sheng. Born in the city slums, Sheng has become a fashionable sign of modernity and cosmopolitanism for the Kenyan youth. Sheng uses mainly the Swahili grammar and syntax, but includes terms from other languages that can vary depending on the different environments.

http://snipurl.com/gn4j