Intonation uses changes in the pitch of the voice to convey meaning.

Intonation carries information that is not provided by the stream of consonants and vowels. It might tell the listener whether the sentence is a question or a statement, or whether more will follow. Intonation may also signal differences in meaning or in attitude.

More technically, it is the part of the sound system of a language which involves the use of pitch to convey information. It consists of both accent (concerns individual words) and sentence melody (concerns word groups).