The main functions of intonation (according to David Crystal)

1. Emotional – to express a wide range of attitudinal meanings.

2. Grammatical – to mark grammatical contrasts.

3. Information structure – to convey what is new and what is already known in the meaning of an utterance.

4. Textual – to construct larger than utterance stretches of information.

5. Psychological – to organize language into units that are more easily perceived and memorized.

6. Indexical – to serve as markers of personal identity.