Practise speaking alone- talk to youself at home to build up your confidence. Then try to arrange to speak to someone in a non-professional situation and get used to doing it before speaking in professional situations. Ultimately, you have to overcome the fear, so fight it. I am learning Khmer at the moment. I started with nothing and speak it badly now, but I can make myself understood, so I am not afraid. The fear is in your mind- when you are speaking a foreign language, you are doing the hard work, not the listener. Above all, keep trying.