Macaronic language is any expression using a mixture of languages, particularly bilingual puns or situations in which the languages are otherwise used in the same context (rather than simply discrete segments of a text being in different languages). Hybrid words are effectively "internally macaronic". In spoken language, code-switching is using more than one language or dialect within the same conversation.

Macaronic Latin in particular is a jumbled jargon made up of vernacular words given Latin endings or of Latin words mixed with the vernacular in a pastiche (compare dog Latin).

The word macaronic comes from the Neo-Latin macaronicus, which is from the Italian maccarone, or "dumpling", regarded as coarse peasant fare. It is generally derogatory and used when the mixing of languages has a humorous or satirical intent or effect but is sometimes applied to more serious mixed-language literature.

Texts that mixed Latin and vernacular language apparently arose throughout Europe at the end of the Middle Ages—a time when Latin was still the working language of scholars, clerics and university students, but was losing ground to the vernacular among poets, minstrels and storytellers.

An early example is from 1130, in the Gospel book of Munsterbilzen Abbey. The following sentence mixes late Old Dutch and Latin:

Tesi samanunga was edele unde scona
et omnium virtutum pleniter plena

Translated: This community was noble and pure, and completely full of all virtues.

The Carmina Burana (collected c.1230) contains several poems mixing Latin with Medieval German or French. Another well-known example is the first stanza of the famous carol In Dulci Jubilo, whose original version (written around 1328) had Latin mixed with German, with a hint of Greek. While some of those early works had a clear humorous intent, many use the language mix for lyrical effect.