Gikuyu or Kikuyu (Gikuyu: Gĩkũyũ, pronounced [ɣēkōjó]) is a language of the Bantu family spoken primarily by the Kikuyu people of Kenya. Numbering about 6 million (22% of Kenya's population), they are the largest ethnic group in Kenya. Gikuyu is spoken in the area between Nyeri and Nairobi. Gikuyu is one of the five languages of the Thagichu subgroup of the Bantu languages, which stretches from Kenya to Tanzania. The Gikuyu people usually identify their lands by the surrounding mountain ranges in Central Kenya which they call Kirinyaga.
Gikuyu has four main mutually intelligible dialects. The Central Province districts are divided along the traditional boundaries of these dialects, which are Kirinyaga, Muranga [Maragua], Nyeri and Kiambu. The Gikuyu from Kirinyaga are composed of two main sub-dialects - the Ndia and Gichũgũ who speak the dialect Kĩ-Ndia and Gĩ-gĩcũgũ. The Gĩcũgũs and the Ndias do not have the "ch" or "sh" sound, and will use the "s" sound instead, hence the pronunciation of "Gĩcũgũ" as opposed to "Gĩchũgũ". To hear Ndia being spoken, one needs to be in Kerugoya the largest town in Kirinyaga. Other home towns for the Ndia, where purer forms of the dialect are spoken will be in the tea growing areas of Kagumo, and the cool Kangaita hills. Lower down the slopes is Kutus, which is a bustling dusty town with too many influences from the other dialects to be able to differentiate.
The unmistakable sing-song Gichugu dialect (which sounds like Embu, a sister language to Gikuyu) can be heard in the coffee growing areas of Kianyaga, Gĩthũre, Kathũngũri, Marigiti. The Gichugu switch easily to the other plainer Kikuyu dialects in conversation with the rest of the Gikuyu.
The Mwea division, which is part of the Kirinyaga District, is an amalgam of Gikuyu, mostly from Kirinyaga, settled in the mid to late 1960s, soon after independence, by displaced Gikuyu whose lands had been taken by the colonialists.
There is a notable literature written in the Gĩkũyũ language. For instance, Ngũgĩ wa Thiong'o's Mũrogi wa Kagogo (Wizard of the Crow) is the longest book written in a sub-Saharan African language. Other authors writing in Gĩkũyũ include Mwangi wa Mutahi, Gatua wa Mbugwa and Waithĩra wa Mbuthia. Mbuthia has published various works in different genres--essays, poetry, children stories and translations--in Gĩkũyũ language. The late Wahome Mutahi also wrote some of his literature in Gĩkũyũ.