lingua franca (lĭngˈgwə frăngˈkə) [key], an auxiliary language, generally of a hybrid and partially developed nature, that is employed over an extensive area by people speaking different and mutually unintelligible tongues in order to communicate with one another. Such a language frequently is used primarily for commercial purposes. Examples are the several varieties of the hybrid pidgin English (see pidgin); Swahili, a native language of E Africa (see Swahili language); Chinook jargon, a lingua franca formerly used in the American Northwest that was a mixture of Chinook, other Native American languages, English, and French; and a variety of Malay (called bazaar Malay ), which served as a compromise language in the area of British Malaya, the Dutch East Indies, and neighboring regions (see Malayo-Polynesian languages). The original lingua franca was a tongue actually called Lingua Franca (or Sabir) that was employed for commerce in the Mediterranean area during the Middle Ages. Now extinct, it had Italian as its base with an admixture of words from Spanish, French, Greek, and Arabic. The designation "Lingua Franca" [language of the Franks] came about because the Arabs in the medieval period used to refer to Western Europeans in general as "Franks." Occasionally the term lingua franca is applied to a fully established formal language; thus formerly it was said that French was the lingua franca of diplomacy.
See H. R. Kahane et al., The Lingua Franca in the Levant (1958); R. A. Hall, Jr., Pidgin and Creole Languages (1966); B. Heine, Status and Use of African Lingua Francas (1970).