Before you can teach students how to speak, they must first study and observe those who do speak. Ask students to listen to a political address or watch Martin Luther King, Jr.'s "I Have a Dream" speech. Have them take notes on the speaker's mannerisms, etiquette, topic and method of engaging with the audience. Discuss the techniques in class, and explain how your students can apply them to their own style.
To engage an audience completely, students must understand their audience and the skills they need to communicate confidently and effectively with that audience. Have students choose a mock career that would require them to give a speech --- a politician, a businessman or a news anchor, for example. Discuss eye contact, hand gestures, posture, enunciation and pronunciation, vocabulary, pauses and rate of speaking. Have them write a speech for the career they chose that would engage their audience.
Assign each student a day to give their speech. Instruct them to dress professionally. Girls should pull their hair back away from their face and wear modest jewelry. Have them stand before the class and present their speech. Time it so they learn to present under a deadline. At the end of each speech, discuss what each of your students did correctly and what they should improve on. Practicing teaches students to listen and critique a speech as well as practice and improve their own speaking style in a safe environment.
Have your students write a short essay on how they could improve, what they would do differently and how they felt as they gave their first speech. Continue this technique over the course of the semester. Divide students into pairs to practice giving short, impromptu speeches so they can practice their techniques. As students continue to practice, their technique and confidence will improve, and the skill will stay with them as they continue into the working world.