Language contact occurs when speakers of two or more languages or varieties interact with and influence each other. The study of language contact is called contact linguistics. Language contact can occur at language borders,[1] between adstratum languages, or as the result of migration, with an intrusive language acting as either a superstratum or a substratum.
When speakers of different languages interact closely, it is typical for their languages to influence each other. Intensive language contact may result in language convergence or relexification. In some cases a new contact language may be created as a result of the influence, such as a pidgin, creole, or mixed language. In many other cases, contact between speakers occurs with smaller-scale lasting effects on the language; these may include the borrowing of loanwords, calques, or other types of linguistic material.
Multilingualism has been common throughout much of human history, and today most people in the world are multilingual.[2] Multilingual speakers may engage in code-switching, the use of multiple languages in a single conversation.
Methods from sociolinguistics[3] (the study of language use in society), from corpus linguistics and from formal linguistics are used in the study of language contact.