people don't hear me and im asked to repeat.

people don't hear me and im asked to repeat. Hi, i posted on this sub before about a problem of mine, when i talk people don't hear me and im asked to repeat. Some of y'all said if you can ask a close friend of yours if he can tell you whats really happening. So i did, and he told me that my voice is not low and its clear but i don't understand what you're saying, so after questioning him it looks like I developed a bad habit from my stuttering, i talk fast and I don't get the articulation of letter sounds right, now i atleast know whats up, but who can i fix it?