This story demonstrates the problem when one uses incorrect tones.
I didn't write this story. I just heard it told on a youtube video.
不是， 而是 一口人。
I want to tell you a funny story. A person received a call. The other person said, I'm census takers. Please answer, "How many people are in your house?"
He said that one person.
No, but a person.
In fact, one person.
Just one person.
funny joke, I can understan it.
Such misunderstandings exist in reality.
Funny but the joke does show how speaking correct tones is important to communication.