You can start with reading for initial days to understand the technique. Also voice record yourself & listen it to know how it feels (sometimes we feel it is too slow but when you listen it , it does not appear too awkward) After that start with speaking with yourself on any random topic you want , additionally think of any scenario (like buying groceries) & assume in mind someone is standing infront of you, & practice the conversation. Simultaneously with above practice, try using it in real life conversations too. Like I said earlier, you might not be able to use 100% of times but atleast keep trying for whatever you can. Along with this, work on your mind to get less attached to what people will think about your talking speed (again this will also take think & cannot happen in one day, but keep working on it ) This prolongation technique is not something you want to do all your life but doing it for sometime will improve your confidence (if you are able to speak words with less blocks) & slowly your talking rate will automatically improve. Speaking slowly is still better than 3-5 seconds long blocks, right ?