Same for me. I struggle the most at the beginning of a sentence, especially when I have to introduce myself. But different tactics work for different people. Once I struggle on a certain word or a letter at the beginning of a sentence, then it's kind of stuck in my head. And as long as it is on my mind, then I can't get past it. At times, I may start a sentence off with saying "K" under my breath so I can start talking. Even sometimes have to kind of loudly say "SO' and then start talking.