| Term | Definition |
| creole | Ethnic term first applied in the Caribbean region to the native-born descendants of the Spanish conquerors and their local consorts. |
| creolization | In a linguistic context, the process describing the convergence of two or more languages, forming a separate, new language. |
| Esperanto | A made-up Latin-based language, which its European proponents in the early twentieth century hoped would become a global language. |
| lingua franca | A term deriving from "Frankish Language" and applying to a tongue spoken in ancient Mediterranean ports that consisted of a mixture of Italian, French, Greek, Spanish, and even some Arabic. |
| monolingual states | Countries where only one language is spoken. |
| multilingual states | Countries where two or more languages are spoken. |
| official language | In multilingual countries the language selected, often by the educated and politically elite, to promote internal cohesion. |
| pidgin | A lingua franca that has been simplified and modified through contact with other languages. |
| toponymy | The study of the origins and meaning of place-names. |