Sheng is a Swahili-based patois or slang-based language, originating in Nairobi, Kenya, and influenced by the many languages spoken there. The word is coined from the two words - (S)wahili and (Eng)lish.
While primarily a language of urban youths, it has spread across social classes to the halls of the Kenyan parliament and geographically to neighbouring Tanzania and Uganda.
Originating in the early 1970s in the Eastlands area of Nairobi (variously described as a 'slum', 'ghetto' or 'suburb'), Sheng is now heard among matatu drivers across the region, and in the popular media. Most of the Sheng words are introduced in various communities and schools and given wide exposure by music artists who include them in their lyrics, hence the rapid growth. It can be assumed to be the first language of many Kenyans in urban areas. Like all slang, it is mainly used by the youth and is part of popular culture in this country. It also evolves rapidly, as words are moved into and out of slang use. It is finding broad use among East African hip hop artists, both mainstream and "underground", whose music helps spread the language and contribute to rapid changes or shifts in Sheng vocabulary, but also among university and secondary-school students. Although the grammar, syntax, and much of the vocabulary are drawn from Swahili, Sheng borrows from English and from the languages of the various ethnic groups in Kenya, including Gĩkũyũ, Luo and Kamba. Words are also borrowed from languages that are neither a local language nor English — such as the Sheng word dame "lady" — which is a title of honour for a lady in English, or morgen "morning" - a Sheng word used in some areas with a similar meaning in German.
Analysts of Kenyan education have claimed Sheng is a bad influence to education stating "The overbearing influence of Sheng is a leading cause of bad performance in Swahili among pupils."
Sheng vocabulary can vary significantly among regions of Kenya and East Africa, and even neighbourhoods of Nairobi. Most of the youth living in Nairobi often use Sheng as their everyday language rather than speak fluent Swahili or English.
Some examples of popular Sheng words are manzi or mresh which means "girl", beste which means "friend", "muenjoyo" which means "having fun", hanye which means "to go out at night" and waka which means "to get drunk".