Quick answer
The wise person can take instruction; the fool is too busy talking to hear any, and he falls.
Read both lines
The first line locates wisdom in an unexpected posture: receiving. Teachability is not the beginner's phase of wisdom that you eventually graduate from; in Proverbs it is the permanent shape of a wise heart. Opposite him stands the "prating fool," literally a fool of lips, all output, lips flapping, nothing arriving. The consequence lands with a thud: he will fall, not because talking is dangerous in itself, but because a person always transmitting never receives the correction that would have caught him. The fall is built into the deafness. The same second line returns at 10:10: the fool of lips falls in more than one scene.
Related: Proverbs 10:10 · Proverbs 12:15
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.