Reluctance to express one's ideas in a postgraduate environment surprises me as a facilitator. Probably, it is the cultural or social back ground. Sometimes, I feel that they grow underconfident due to their pre conceived knowledge gap. They think they need to know everything.
I asked them to Read the speech of Susan B. Anthony (Link given below). Then, trace and track the logic she uses for citizen’s right to vote.
https://voicesofdemocracy.umd.edu/anthony-is-it-a-crime-speech-text.
I could feel the fear. I explained a couple of techniques to facilitate them, gave them a free hand to make their own effort. They understand the crux, rather relate to it as well. However, the fear of expression: written as well as oral is perceived. Suggest, what comes to your mind. Thanks