Help on the letters A and I ?

Help on the letters A and I ? Hello, i have speech blocks with the letters K, P , A and I. The K and P have been getting better recently and I can easily prolong it if I block with it sounding pretty natural. I used to stutter on the letter T and D too but suddenly they switched with A and I and idk how. It's unnatural too prolong them especially if it's just a one word answer. Does someone know how to say them easily when a deep breath doesn't work?