Answer :
When speakers lack confidence, they are more likely to stutter or stammer, or interject verbal crutches like um or uh, which can be distracting to your listening audience. When you practice, you get to know your material very well. As a result, you spend less mental energy on remembering the words and more energy on all the elements that make your speech more compelling: varying the pitch and tone of your voice, adding gestures, and maintaining eye contact.