Encourage children to talk during different portions of the day, and provide opportunities within your school day for discussion. This need not be monitored, and it does not need to be about a particular subject. Discussions about any subject, between any number of students, help all students feel comfortable with speaking patterns and with speech in general.
Provide opportunities for small group discussions in each of your classes throughout the day. Encourage students to discuss the lesson you just went over, or to work through particular problems within a class by speaking to one another or working together in a group. Allowing students to talk about an assignment or to talk as part of a lesson encourages them to develop speech habits that they can use later in life as well as throughout the rest of their education.
Ask students if they have any questions several times during a lesson, and be patient as you wait for questions. Allow students to ask questions about the lesson whenever they wish. This encourages students to talk, and also discourages students from feeling as though what they have to contribute vocally is not important.
Provide opportunities in each class, at each grade level, for students to speak in front of a group. From Show and Tell in early grade levels to advanced speeches in upper grade levels, getting up and talking in front of peers helps language and speech develop and also helps all students gain confidence.