In linguistics, intonation is the variation in pitch used to indicate the speaker's attitudes and emotions, to highlight or focus an expression, to signal the illocutionary act performed by a sentence, or to regulate the flow of discourse. For example, the English question "Does Maria speak Spanish or French?" is interpreted as a yes-or-no question when it is uttered with a single rising intonation contour, but is interpreted as an alternative question when uttered with a rising contour on "Spanish" and a falling contour on "French". Although intonation is primarily a matter of pitch variation, its effects almost always work hand-in-hand with other prosodic features. Intonation is distinct from tone, the phenomenon where pitch is used to distinguish words (as in Mandarin) or to mark grammatical features (as in Kinyarwanda).

Most transcription conventions have been devised for describing one particular accent or language, and the specific conventions therefore need to be explained in the context of what is being described. However, for general purposes the International Phonetic Alphabet offers the two intonation marks shown in the box at the head of this article. Global rising and falling intonation are marked with a diagonal arrow rising left-to-right [↗︎] and falling left-to-right [↘︎], respectively. These may be written as part of a syllable, or separated with a space when they have a broader scope:

Here the rising pitch on street indicates that the question hinges on that word, on where he found it, not whether he found it.

Here, as is common with wh- questions, there is a rising intonation on the question word, and a falling intonation at the end of the question.

In many descriptions of English, the following intonation patterns are distinguished:

It is also common to trace the pitch of a phrase with a line above the phrase, adjacent to the phrase, or even through (overstriking) the phrase. Such usage is not supported by Unicode as of 2015, but the symbols have been submitted. The following example requires an SIL font such as Gentium Plus, either as the default browser font or as the user-defined font for IPA text, for which see Template:IPA#Usage.

All vocal languages use pitch pragmatically in intonation—for instance for emphasis, to convey surprise or irony, or to pose a question. Tonal languages such as Chinese and Hausa use intonation in addition to using pitch for distinguishing words. Many writers have attempted to produce a list of distinct functions of intonation. Perhaps the longest was that of W.R. Lee, who proposed ten. J.C. Wells and E. Couper-Kuhlen both put forward six functions. Wells's list is given below; the examples are not his:

It is not known whether such a list would apply to other languages without alteration.