As a child I was always told off when I said "I can't" my Mum or Dad would say "Can't means Won't!" I am a lot older know, but you know what? They are right!
So many students don't start lessons because they feel they CANT do it. Maybe someone has told them that they are not good enough, or that they won't manage to learn to speak English.
I have just recently been given a part in a one man play that I will be performing in the Summer, however it requires me learning the lines. "I can't do lines" was the first thing I said. However a very wise person took me aside and helped me to see that by saying I cant I am imprinting on my mind the inability to do that task.
However, what I should say is that I have not done that before! So now I need to say I will do this. I will learn to say my lines, I know that I will need to work hard but I CAN DO IT!
So if you are scared of failure, remember you only fail when you stop trying, until then you just haven't made it YET!