Language exchange is a method of language learning based on mutual language practicing by learning partners who are speakers of different languages. Language exchange is sometimes called Tandem language learning.
In modern contexts, "language exchange" most often refers to the mutual teaching of partners' first languages. Language exchanges are generally considered helpful for developing language proficiency, especially in speaking fluency and listening comprehension. Language exchanges that take place through writing or text chats also improve reading comprehension and writing ability. Given that language exchanges generally take place between native speakers of different languages, there is also the side benefit of improving cross-cultural communication.
This practice has long been used by individuals to exchange knowledge of foreign languages. For example, John Milton gave Roger Williams an opportunity to practice Hebrew, Greek, Latin, and French, while receiving lessons in Dutch in exchange.