This chapter introduces language invention. It addresses the similarities and differences between natural languages (natlangs) and constructed languages (conlangs) and distinguishes the latter from creative language forms such as slang and language games. This chapter also covers the main types of conlangs and the key motivations underlying language invention. It also discusses important considerations to keep in mind when creating a language and provides a guided exercise on language invention. The chapter ends with a list of resources and references to explore further.

Esperanto was created in the nineteenth century by the Warsaw-based ophthalmologist L. L. Zamenhof (1859–1917) as a universal second language; he called it Lingvo Internacia, the international language, hoping that it would foster global peace and understanding. Esperanto isn’t the only constructed language, but it is the most popular; it is also the one with the richest cultural legacy and a complex history of dictionaries. Offering a comparative analysis of the dictionary tradition of Esperanto, this conversation compares that tradition to other languages. Ludovik Zamenhof is discussed as the seminal figure in that tradition. It looks at translation as a force changing Esperanto, reflects on the tension between particularism and universalism, and questions Esperanto’s Eurocentrism. It meditates on how the internet has changed Esperanto lexicography. Finally, it explores canonical lexicons such as the Baza Radikaro Oficiala, published under the aegis of the Academy of Esperanto, as well as the Plena Vortaro de Esperanto, released by the Sennacieca Asocio Tutmonda, as well as Kazimierz Bein’s Vortaro de Esperanto, and the Plena Ilustrita Vortaro.