You can actually do this by yourself, if you try very hard. Just practice slowing down and enunciating each word fully, no slurring of the words. My son had the same problem and he has now slowed down to where everyone understands him. Part of what might be causing this is that you speed talk when you are nervous or insecure about a situation..when you are IN one of those situations, just mentally prepare yourself and make yourself slow down your speaking..think on every sentence you are going to say and then say it properly. Best of luck!!!