Establish the ground rules and norms for class discussion early on. By setting the standards for class participation as early as possible, your students will be more likely to understand their role in discussion. Specific elements, such as when a speaker should raise their hand, and more intangible aspects such as the tone for the classroom environment you establish, will help your students understand how communication works within the classroom.
Encourage all students to participate in class discussion. Avoid focusing on the students that are always willing to answer. Look for responses from the entire classroom, and be willing to take the time for them to emerge.
Assign frequent opportunities for small group discussion. The more often students work together in order to contribute to the larger discussion, the more comfortable they will become within the classroom environment, increasing their willingness to communicate.
Adopt a policy of openness with your students. When you make a change to the class structure, or give an assignment, be open with your students about your intentions, and seek their feedback. By treating them with respect and openness, you will help foster an environment of trust with your students, increasing their likelihood of open communication.