May sound silly, but before you say the word, take a short pause, breathe, and say it slowly? It seems stupid to suggest, but it helps me a lot, but it only helps me in work. Outside of work, I can't keep up the slow pace for some reason. I have a habit of speaking too fast, which also means I don't breathe in between my words where if I speak more slowly, I can speak a lot more clearly and pronounce words a little better.