I have big trouble when I'm speaking out my vowels in general and is more noticeable when Im excited or angry. Especially when its at the beginning of a word. But I usually block more on consonants like C (in words like "cut") and M, mostly. But I've recently started getting these, I guess facial tics? where my mouth widens when I'm pronouncing a vowel and it looks so grotesque. Trust me, you're not the only one 😄