Efik /ˈɛfɪk/ EF-ik (Usem Efịk) is the indigenous language of the Efik people, who are situated in the present-day Cross River State and Akwa Ibom State of Nigeria, as well as in the north-west of Cameroon. The Efik language is mutually intelligible with other lower Cross River languages such as Ibibio, Anaang, Oro and Ekid but the degree of intelligibility in the case of Oro and Ekid is unidirectional; in other words, speakers of these languages speak and understand Efik (and Ibibio) but not vice versa. The Efik vocabulary has been enriched and influenced by external contact with the British, Portuguese and other surrounding communities such as Balondo, Oron, Efut, Okoyong, Efiat and Ekoi (Qua).

The Efik Language has undergone several linguistic classifications since the 19th century. The first attempt at classifying the Efik language was by Dr. William Balfour Baikie in 1854. Dr Baikie had stated, "All the coast dialects from One to Old Kalabar, are, either directly or indirectly, connected with Igbo, which later Dr. Latham informed that, it is certainly related to the Kafir class". The Kafir Class was a derogatory term used to describe the Bantu languages. Thus, Dr Baikie attempts to classify the Efik Language as linked to the Bantu languages. The next attempt to classify the Efik language was by Rev. Hugh Goldie who classified the Efik Language as one of the Northern Languages which he states, "forms by far the greater part of its as the Semitic class does, from the root of the verb." Another attempt was made by Westermann who classified the Efik languages as belonging to the West Sudan group of the Sudanic languages. The present linguistic classification was made by Greenberg who groups Efik in the Benue-Congo sub-family of the Niger-Congo family. One of the criteria of the inclusion of the Efik language into the Niger–Congo family is its morphological feature. According to Greenberg, "the trait of the Niger–Congo morphology which provides the main material for comparison is the system of noun classification by pair of affixes." Due to the large number of synonyms in the Efik vocabulary, scholars like Der-Houssikian criticised Greenberg's linguistic classification stating, "Ten of the Efik entries have in Goldie's dictionary several synonyms. This immediately brings up the possibility of differing connotations and nuances of meaning. Such differences are not defined by Goldie. These exceptions reduce the number of non-suspicious itens from 51 to 36." Faraclass in his study of Cross River Languages, classified the Efik language as a member of the Lower Cross sub-group of the Delta-Cross group which is an extension of the larger Cross River group that is a major constituent of the Benue Congo subfamily.

The Efik language was first put into writing in 1812 by Chief Eyo Nsa, also known as Willy Eyo Honesty. The following words were obtained from Chief Eyo Nsa by G. A. Robertson:

Prior to the documenting of words in the Efik language by Chief Eyo Nsa, several traders in old Calabar could read and write and had kept journals albeit in the English language. The earliest written letter from the chiefs of Old Calabar dates to 1776. Thus, the literary ground for the Efik language had already been prepared prior to the arrival of the missionaries. When the United Presbyterian Church of Scotland Mission arrived Old Calabar in 1846, Reverend Hope Waddell and Samuel Edgerley with the assistance of the Efik trader Egboyoung (Ekpenyong) started the recordings of Efik vocabulary; these were printed in their lithographic press and made ready in 1849. On the arrival of the missionaries, there was the problem of creating an appropriate orthography for the Efik Language. The orthography chosen by the missionaries was developed by Dr. Lepsius whose system and the phonetic alphabet were found to be suitable for the Efik language at the time. The first Efik dictionary was later released in 1862 by Rev. Hugh Goldie and the Efik orthography was developed in 1874 by Goldie. The Efik language flourished in written literature in which the missionaries and the Efik respectively, played a leading role. Early religious works translated in the Efik language included The Old Testament which was completed by Alexander Robb in 1868 and printed in 1873; Paul's Epistle to the Hebrews translated and published by William Anderson. Indigenous ministers equally contributed to the expansion of the Efik religious literature. Reverend Esien Esien Ukpabio, the first Efik minister ordained in 1872, translated into Efik, Dr. J.H. Wilson's "The gospel and its fruits". Asuquo Ekanem who was equally an Efik minister translated John Bunyan's Holy war into Efik. The Efik people equally began to write Church hymns and publish them. William Inyang Ndang who had spent some time in Britain was the first Efik to introduce a choir into churches at Calabar and had contributed to a large number of Church hymns together with his wife, Mrs Jane Ndang. Between the 1930s to 1950s, Magazines, Newspapers and periodicals were published in the Efik language. From the early 1930s, there was a twelve-page quarterly magazine in Efik, "Obụkpọn Obio" (Town Bugle) edited by Reverend James Ballantyne. The work was designed for the general reader and featured a range of topics, from Usuhọde ye Uforo Obio (The decline and prosperity of a town) to Ufọk Ndọ (Matrimonial home) and other similar topics. This was followed in the 1940s by "Un̄wana" (light), a monthly periodical of 32 pages, edited by E.N. Amaku. From 1948 to 1950, an eight-page weekly newspaper in Efik, "Obodom Edem Usiahautin" (Eastern Talking Drum), edited by Chief Etim Ekpenyong and printed at the Henshaw Press was sold at 2d each. It supplied regular world news (Mbụk n̄kpọntibe ererimbuot) and was widely read. Thus, the Efik language has enjoyed a lot of scholarship since the arrival of the Christian missionaries in 1846.

Due to the extensive trading activities of the Efik people, the language became the lingua franca of the Cross River region. According to Offiong and Ansa,

The Efik language over the years has developed to a level that it dominates other languages spoken around Cross River State. A language like the Kiong language spoken by the Okoyong people is extinct because its speakers have imbibed the Efik language over the years. The same is also said of the Efut language spoken by the Efut people in Calabar South, Apart from being the language that is spoken by a third of Cross River State as an L1, it is the L2 or L3 of most Cross River indigenes. For the purpose of advertising, the language is most used after English in the state. Television and Radio commercials are aired everyday in different spheres, In politics the language is used by all in the Southern senatorial and parts of the Central Senatorial Districts of the State. In education, there is a primary and secondary curriculum of Efik in schools. In the development of linguistics, it is studied at the undergraduate level in the University of Calabar.

Among the Ibibio, the Efik language was accepted as the language of literature due to a translation of the Bible into Efik by the Church of Scotland mission. The Efik Language equally survived in the West Indies due to the exportation of slaves from the Cross River Region. Words of Efik origin can be found in the vocabulary of the Gullah Geechee people of the United States. Within the diaspora in Cuba, a creolised form of the Efik Language is used in the Abakuá secret society, which has its roots in the Efik Ekpe secret society in Nigeria.

/b/ has several allophones. These allophones are dependent on the position of /b/ in a word. In final positions it occurs as an unreleased stop phonetically represented as [p̚], as in the following imperative verbs. [kop̚] (listen!), [sɔp̚] (quick!), [fɛp̚] (dodge!). /p/ in Efik is only found in final positions and can only be realised as /β/ in intervocalic position, example; [dép] + [úfɔk] = [déβúfɔk]. If it is, however, immediately followed by a consonant, it occurs as a released stop phonetically, as in these examples: