Hii, I understand what you’re saying. I do struggle with vowels at times too. Thankfully my stutter is also very mild and not like major. Mine is mainly certain words and vowels and I try my best to not say them or use different. But one thing that you need to remember is that don’t ket this get to you and in your head. Once you accept it and not bring yourself down with it, the more easier your brain will be more calm and you will be more calm saying certain words. For example, sadly there’s times I stutter with my name and it’s an A vowel. So what I do is when someone asks me what is my name? I don’t say just my name because most likely I will stutter because I think it’s maybe in the moment pressure if you wanna call it. So I would say this” my name is blank” that way it’s smooth and I have a bit of time to say my name smoothly instead of rushing to get it out you know? With me personally, it’s all about smoothness when talking. I always maybe try to add an extra word or two so that way I don’t stutter on the word that maybe is challenging for me. But keep your head up man! The more you’re one with it, the better you will see that you will talk more smoothly and calm in a way. I hope this helps and trust me I’ve had a stutter since I was like 10 years old and I am 23 now. Had it all my life and now I am starting to accept living with it and that’s okay.