We have a choice, to say words like (for example) «yes» or «no» with the pitch remaining at a constant level, or with the pitch changing from one level to another. The word we’ll use for the behaviour of the pitch in this case is «Tone«
For one syllable utterances we can use one of three possobilities: Level, Fall and Rise.
It will be necessary to use symbols to represent tones:
Intonation Patterns 