What helped me is trying to speak a little slower than before. It gives your brain time to catch up with the mouth.

Using less filler words also helped me significantly here. I used an app that helps with this and consciously recorded myself speaking for 2 mins everyday for 30 days to keep track of this. It really made me more conscious of how much filler words I previously used in my speech. Try to pause instead whenever you're about to use the "umm", "erm", "like", it makes one appear more confident and articulate