Good papers are rather rare. He gives students every opportunity to rewrite their work. In smaller classes, students have to write drafts, preferably two. He encourages shy students to have their classmates read their work to the group. Bob uses lots of small groups to encourage communication.
Students can present arguments to each other.
They can visit him during his office hours and present an argument just to him. He helps them hone their ideas. He has tried to show them how shy and incompetent he was, but that didn't work. Bob exercises a lot of patience with shy students. They can work with them or be paired with less shy students.