Well anyone could, however the human body can only perform so many techniques(which is alot) however there are alot of martial arts and to try to make an effective new one is unlikely. especcialy one that is untrained, also people that have no training generaly dont know whats really a real technique and how it really works outside the television box. They would have a hard time using body connection and developing a series of movements that really flow with each other...but it is very possible