Voice When we speak, we use a different tone of voice depending on who we are talking to and the situation. In Unit 2, Professionalism, you learned that the tone you use when dealing with the public can be more important than the actual words you say. When we write, we also use a different tone of voice for different purposes. For example, you would not use the same tone to write a letter to a friend as you would to write a letter asking for a job interview.