Quick answer
Words and work both come back around. The verse puts speech and labor in the same category of things that return to their owner.
Read both lines
Pairing the mouth with the hands is the move here. The first line treats speech as producing fruit, which is the same agricultural frame used of the righteous life at 11:30 and of the root two verses ago, and the second treats work in the ordinary way. Setting them together says that what a person says is as productive, and as consequential, as what a person does. This is observation rather than mechanism. The book is not describing a system that pays out; it is noting that over a lifetime both a person's words and their labor tend to circle back.
Related: Proverbs 11:30 · Proverbs 18:20 · Proverbs 13:2
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.