Why is speaking so difficult for me?

Hey I'm a 16 year old male and the majority of the things you say I can relate to. When I was in elementary school, I took speech therapy that had to do with comprehension & my "brain to mouth function." They told me my brain was thinking faster then my mouth could move and it would sometimes "overwhelm" my mouth. Once I stopped taking therapy in middle school it came back and to this day the majority of the things you've mentioned happen to me. I'm not an expert, but from personal experience I would recommend that before you even say something, make sure your relaxed and know exactly what to say. I know we don't think about what we say but like for me, I'll start saying something and I just lose track of what I'm saying and might mumble. Try and to practice slowing you speech down and overtime you'll become acustom to thinking before you speak and making sure your relaxed enough inorder to avoid trying to get to many words out at once and either mispronounce words or not be able to get a word out. It sounds to me that all of what youve mentioned seems to effect you a lot more than it does to me. So it might not be a bad idea to look into getting some speech therapy, I know I will if my speech starts to really hinder me badly.