A comma tells you when to pause in your speech. A question mark indicates you should raise your voice at the end of the sentence. An exclamation point tells you to emphasize your speech. Knowing the difference between a subject and a verb can help you to understand the meaning of a phrase or sentence. There are SO MANY reasons why good grammar is linked to proper speech! For now, I will leave you with a few examples:
Let's eat, Grandma! vs. Let's eat Grandma.
We like fish. vs. We like to fish.
She is better than that. vs. She was better then.
He was affected by the effect his grammar had on those around him.
Their dancing was the worst and their cooking was even worse.
She even used a ruler to cut the fabric into even strips?