Multilingualism is the use of more than one language by an individual, or the coexistence of multiple languages within a community or institution. It encompasses everyday communication, learning, and the organization of public life. Individual multilingualism does not require equal mastery of every language: speakers may use different languages for different purposes and possess different levels of proficiency in each. Societal multilingualism concerns the distribution and functions of languages, rather than assuming that every member of a society speaks them all. (coe.int)
Definitions and scope
Bilingualism, usually referring to the use of two languages, is commonly treated as a particular form of multilingualism. The terminology varies between research traditions. The Council of Europe distinguishes multilingualism, understood as the coexistence of languages, from plurilingualism, which emphasizes an individual's interconnected and evolving linguistic resources. Other scholars use multilingualism for both individual and societal phenomena, including approaches that treat language knowledge as an integrated repertoire. (rm.coe.int)
A person's linguistic repertoire includes the languages and varieties available for communication. Its components need not be equally developed: someone may read one language proficiently, converse in another, and understand a third without speaking it readily. Repertoires develop through family life, schooling, work, and other social encounters. They also encompass regional varieties and dialects, making the distinction between knowing several languages and using several varieties dependent partly on how those varieties are classified. (coe.int)
Acquisition and individual use
Multilingual repertoires emerge through several pathways. Language acquisition can occur in the home, through interaction with neighbours and peers, or through formal instruction. Languages acquired in different settings often serve different functions. A speaker might use one language for family relationships and another for professional or academic activity; proficiency therefore reflects opportunities and purposes of use rather than a single, uniform ability. (coe.int)
Research on children learning more than one language examines variation in development, exposure, literacy, and assessment. Evaluating multilingual development requires attention to the languages children encounter and the distribution of their skills across those languages. The US National Institutes of Health has identified variability in bilingual development and appropriate assessment as important research areas, alongside questions about language learning and educational experience. (nidcd.nih.gov)
Language knowledge is not static. Learning additional languages, changing social environments, and reduced use can reconfigure an individual's repertoire. The Council of Europe's framework consequently recognizes partial competences and changing proficiency rather than treating a multilingual person as several fully proficient monolingual speakers combined. (coe.int)
Language contact and interaction
Multilingual communication is a major setting for language contact. One prominent practice is code-switching, the alternation of languages or linguistic varieties within an interaction. It occurs in immigrant communities, regional minorities, and established multilingual populations. Research in sociolinguistics examines its relationship to conversational purposes, shared identities, and the social organization of communication. Switching can occur between sentences or within them, and researchers also investigate the grammatical patterns that constrain it. (cambridge.org)
Code-switching is related to, but distinct from, lexical borrowing. Borrowing can establish an expression from one language within another language's vocabulary, often involving adaptation to its phonology and morphology. An established borrowed word may be used by speakers who do not know the source language. The boundary between borrowing and switching is sometimes difficult to draw, particularly for individual words. (assets.cambridge.org)
Contact may also contribute to longer-term changes in vocabulary and grammatical structure. Its outcomes depend on the social circumstances of interaction, and multilingualism does not automatically produce a single predictable pattern of linguistic change. Historical research documents multilingual practices in business writing and other texts, extending the study of contact beyond spoken conversation. (cambridge.org)
Societies and institutions
Societal multilingualism may involve geographically concentrated language communities, several languages used within the same locality, or different languages assigned to particular institutional functions. Recognition as an official language is distinct from the languages people actually use. Switzerland illustrates territorial and institutional multilingualism: German, French, Italian, and Romansh are national languages, while their official functions differ at federal and regional levels. (rm.coe.int)
Language policy shapes how institutions accommodate linguistic diversity. International organizations provide a further example. The United Nations has six official languages: Arabic, Chinese, English, French, Russian, and Spanish. Its multilingual operations depend on translation of documents and interpreting during meetings. These arrangements enable institutional communication without requiring every participant to know every official language. (un.org)
Multilingual education
Multilingual education uses two or more languages in education and may include learners' home languages. It concerns both the teaching of languages as subjects and their use as media for learning other subjects. The distinction matters because studying a language is not equivalent to learning mathematics, history, or science through it. (vocabularies.unesco.org)
UNESCO's guidance addresses the relationship between familiar languages, educational access, and opportunities to learn additional languages. Its 2003 position paper supports first-language instruction while recognizing the importance of access to wider languages of communication. Its 2025 global guidance develops policy principles and implementation resources for multilingual systems. Practical provision involves curricula, teaching materials, teacher preparation, and the relationship between languages used at home and at school; multilingual education therefore extends beyond simply adding another language course. (unesco.org)