Is it possible to become fluent in Mandarin in two years?
YES! Here is a good example
In this video I set four Chinese challenges for him, which are: Quick Q&A, Chinese Rap, Internet Slang and Idioms. His excellent performance in the video proves to us that it is possible to become fluent in Chinese in two years. "Nothing is impossible to a willing mind"- as the old Chinese saying goes. His life story and learning experiences are very inspiring to all of us.