Yeah thats a stutter/block. Try to prolong the first letter of the word you're having trouble with and ease the pressure on it. Eg instead of saying "apple" say "aaaple" and kinda breath into the beginning if that makes sense. One of the biggest things that helps me is to remember to breathe, and remember that the stutter isn't quite as severe as it seems to you. Sometimes when I get caught in a block and nothing comes out it feels like minutes start to pass and I feel like I look like a total imbecile having some kind of seizure which just makes it worse. When I ask my friends about it they say that while its noticeable, I get the word out in a second or two. ​ Ultimately this is something we'll have to deal with the rest of our lives so accepting it is a big part, and one that I struggle with on a day to day basis. ​ I'd highly recommend going to speech therapy if you have the means. It won't cure it, but it will give you tools to deal with it more confidently.