I think the answers here revolving around tackling the state of your mind are spot on. Learning to sit with the thoughts but not engage with them is a very useful skill. Recognise too that fluent speech comes effortlessly without thought of the words. So when you feel you're about to stutter, you may not actually say those words at all or you may say it in a different way. I'm not saying to avoid words, but rather I'm saying realise you don't need to think of the words in the first place. The anticipation you get is a very elaborate trick your mind has played on itself and you don't have to listen to those thoughts. Lastly I would add to be kind to yourself and recognise it takes time for certain mental habits to disappear. You won't stop feeling anticipation overnight. But 100% it can die away into nothingness. But don't count the days, otherwise it will never go away. Make the days count.