start speaking fast because their brain is always in the relaxing joyful alpha-theta brainwaves. Children soak up languages faster because they are joyful, playful and relaxed. They do not control the process. They are open to making mistakes. Students learn to speak by trial and error. They speak, make mistakes and learn from their mistakes.
have trouble opening up to speaking the second language because they are conditioned to control all aspects of their lives. However, the language center in our brain does not want to be controlled. If you want to control it, it will freeze. Learning to speak requires trust, playfulness and zero control.