Quick answer
Answering before hearing is folly wearing its own name tag: a verdict issued before the trial, shaming the judge rather than the defendant.
Read both lines
The first line describes a universal habit precisely: the reply drafted mid-sentence, the mind in rebuttal while the ears are still receiving. The second line files it under two headings: folly, because judgment on half the evidence is broken reasoning, and shame, because the room can see what you did. The verse belongs to the book's jurisprudence of listening (18:17, 17:28), and hearing first is not courtesy but epistemology, the minimum price of knowing what you are talking about. James carried it into the church intact: swift to hear, slow to speak (James 1:19).
Related: Proverbs 18:17 · Proverbs 17:28 · James 1:19
New King James Version®, Copyright © 1982, Thomas Nelson. All rights reserved. Full copyright information. Scripture provided by API.Bible.
Go Deeper
If this verse has been used to put weight on you that it was never carrying, ask about it directly.