Everyone stumbles on words sometimes, some more than others. That doesn't necessarily mean the person has a stutter. Personally, I have a blocking stutter. So when I go to say a word, my throat and jaw clench up and I cant get the sound out, or I hold onto the first syllable until I can release it. Other stutterers, have the repetitive type where they repeat the first sound of a word. Unfortunately, there really isn't anything to help. Speech therapy works for some people, it didn't help me at all. The best thing you can do, is try to remain positive with your speaking ability. Try to not overthink speaking situations. Hope this helps