Nigerian Pidgin is an English-based pidgin or creole language spoken as a kind of lingua franca across Nigeria that is referred to simply as "Pidgin", "Broken English" or "Brokan". It is often not considered a creole language since most speakers are not native speakers, although many children do learn it early. Nonetheless it can be spoken as a pidgin, a creole, or a decreolised acrolect by different speakers, who may switch between these forms depending on the social setting. Its superstrate is English with Hausa, Yoruba and Igbo as the main substrate languages. Ihemere (2006) reports that Nigerian Pidgin is the native language of approximately 3 to 5 million people and is a second language for at least another 75 million. Nigerian Pidgin is also spoken across West Africa, in countries such as Ghana, and Cameroon.
Each of the 250, or more, ethnic groups in Nigeria can converse in this language, though they usually have their own additional words. For example, the Yorùbás added the words 'Şe' and 'Abi' to the language. These are often used at the start or end of an intonated sentence or question. For example, "You are coming, right?" becomes "Şe you dey come?" or "You dey come abi?" Another example the Igbos added the word, "Nna" also used at the beginning of some sentences to add effect to the meaning of their sentence. For example, "that test was hard" becomes "Nna men, dat test had no be smal".
Nigerian Pidgin also varies from place to place. Dialects of Nigerian Pidgin may include the Lagos, Onitsha, Benin City, and Ibadan dialects. Sometimes the language may vary even in different parts of the same city.
Nigerian Pidgin, along with the various pidgin and creole languages of West Africa, displays a remarkable similarity to the various dialects of English found in the Caribbean. Linguists hypothesize that this stems from the fact that the majority of slaves taken to the New World were of West African origin, and many words and phrases in Nigerian Pidgin can be found in Jamaican Creole (also known as Jamaican Patois or simply Patois) and the other creole languages of the West Indies. The pronunciation and accents often differ a great deal, mainly due to the extremely heterogeneous mix of African languages present in the West Indies, but if written on paper or spoken slowly, the creole languages of West Africa are for the most part mutually intelligible with the creole languages of the Caribbean. The presence of repetitious phrases in Jamaican Creole such as "su-su" (gossip) and "pyaa-pyaa" (sickly) mirror the presence of such phrases in West African languages such as "bam-bam", which means "complete" in the Yoruba language. Repetitious phrases are also present in Nigerian Pidgin, such as, "koro-koro", meaning "clear vision", "yama-yama", meaning "disgusting", and "dorti-dorti", meaning "garbage". Furthermore, the use of the words of West African origin in Jamaican Patois, such as "boasie" (meaning proud, a word that comes from the Yoruba word "bosi" also meaning "proud") and "Unu" - Jamaican Patois or "Una" - West African Pidgin (meaning "you people", a word that comes from the Ibo word "unu" also meaning "you people") display some of the interesting similarities between the English pidgins and creoles of West Africa and the English pidgins and creoles of the West Indies, as does the presence of words and phrases that are identical in the languages on both sides of the Atlantic, such as "Me a go tell dem" (I'm going to tell them) and "make we" (let us). Use of the word "deh" or "dey" is found in both Jamaican Patois and Nigerian Pidgin English, and is used in place of the English word "is" or "are". The phrase "We dey foh London" would be understood by both a speaker of Patois and a speaker of Nigerian Pidgin to mean "We are in London". Other similarities, such as "pikin" (Nigerian Pidgin for "child") and "pikney" (or "pikiny"--Jamaican Patois for "child") further demonstrate the linguistic relationship.
The most important differences to other types of English is that there are only some consonants, vowels (6) and diphthongs (3) used. This produces a lot of homophones (words sound the same with different meanings), like thin, thing and tin which are all three pronounced like /tin/. This circumstance gives a high importance to the context, the tone, the body speech and any other ways of communication for the distinction of the homophones.
Some examples include,
Wetin dey happen means What is happening?
I no no, I no know, Me no no or Me no know means I don't know
Come chop means Come & eat

See also

Shnukal, Anna and Lynell Marchese. 1983. "Creolization of Nigerian Pidgin English: a progress report." English World-wide 4: 17-26.
Ihemere, Kelechukwu Uchechukwu. 2006. "A Basic Description and Analytic Treatment of Noun Clauses in Nigerian Pidgin." Nordic Journal of African Studies 15(3): 296–313.