A person who speaks carefully does not have to constantly repair what they meant.

Careless speech creates a stream of repair work: clarifying, apologising, explaining what you actually meant. Someone who chooses their words with a little more care up front spends much less time on that maintenance, and their words carry more because they are not routinely being revised.

Slow down slightly in the moments that matter. A second of thought before speaking is a small cost against the alternative. If you are frequently repairing, notice which situations produce it: usually a specific kind of hurry, irritation, or wanting to seem quick.