Lingua francas have developed around the world throughout human history, sometimes for commercial reasons (so-called "trade languages") but also for cultural, religious, diplomatic and administrative convenience, and as a means of exchanging information between scientists and other scholars of different nationalities. The term originates with one such language, Mediterranean Lingua Franca. A world language is the idea of a global lingua franca.
Lingua franca is a functional term, independent of any linguistic history or language structure. Pidgins and creoles often function as lingua francas, but many such languages are neither pidgins nor creoles.
Whereas a vernacular language is used as a native language in a community, a lingua franca is used beyond the boundaries of its original community and is used as a second language for communication between groups. For example, English is a vernacular in the United Kingdom but is used as a lingua franca in the Philippines and India. Russian, Mandarin Chinese, Arabic, Spanish, Portuguese, and French serve a similar purpose as industrial/educational lingua francas in many areas.
The term lingua franca derives from Mediterranean Lingua Franca, the language that people around the Levant and the eastern Mediterranean Sea used as the main language of commerce and diplomacy from late medieval times, especially during the Renaissance era, to the 18th century. At that time, Italian-speakers dominated seaborne commerce in the port cities of the Ottoman Empire and a simplified version of Italian, including many loan words from Greek, Old French, Portuguese, Occitan, and Spanish as well as Arabic and Turkish came to be widely used as the "lingua franca" (in the generic sense used) of the region.