Interlinguistics, as the science of planned languages, has existed for more than a century as a specific branch of linguistics for the study of various aspects of linguistic communication. Interlinguistics is a discipline formalized by Otto Jespersen in 1931 as the science of interlanguages, i.e. contact languages tailored for international communication. In more recent times, the object of study of interlinguistics was put into relation with language planning, the collection of strategies to deliberately influence the structure and function of a living language. In this framework, interlanguages become a subset of planned languages, i.e. extreme cases of language planning.
Interlinguistics first appeared as a branch of studies devoted to the establishment of norms for auxiliary languages, but over its century-long history it has been understood by different authors more and more broadly as an interdisciplinary branch of science which includes various aspects of communication, language planning and standardization, multilingualism and globalisation, language policy, translation, sociolinguistics, intercultural communication, the history of language creation and literature written in planned languages (international auxiliary languages (auxlangs) as well as constructed languages : conlangs), fictional artistic languages (artlangs), lingua francas, pidgins, creoles and constructed languages in the internet and other topics were added.
The hybrid term was first coined in French (as Interlinguistique) by the Belgian Esperantist Jules Meysmans.
The main historical periods of interlinguistics are:
first, the pioneer era (1879–1911), when its basis was put forth;
secondly, the foundational era (1911–1951), when the interlinguistics wars took place to decide the most appropriate form of an auxiliary language;
thirdly, the school era (1951–1990), when independent Interlinguistics schools formed in different countries, mainly Germany, Hungary, Italy, the Netherlands, and Poland, each with particular attention to Esperanto;
lastly, the current era of language policy (1990–today), during which interlinguistics is more tightly integrated with other disciplines, mainly linguistics and various social and political sciences, particularly via the topics of globalism, linguistic justice, management of multilingualism, and new forms of mobility.