Pitch movement is the way the quality of the voice changes as a speaker communicates. Pitch is produced by the vibration of the vocal folds. When meaning is also considered, this is known as tone. English is an example of an intonational language, which uses pitch change across words and phrases to communicate meaning, especially attitude.
An English speaker changes the pitch of their voice to communicate sarcasm.
In the classroom
Pitch movement itself is not studied but the way it is used to communicate meaning (tone and intonation) is.