Besides avoiding monotone, another reason to fluctuate your pitch during your speech is to express stress in words
This refers to the passage of information between different people with the use of a medium and expecting feedback.
With this in mind, we can see that the use of pitch while speaking is to express an emotion or attitude when speaking which would help the readers to understand the author and it is also used to express stress in words.
Read more about communication here:
https://brainly.com/question/26152499