Tone
Tone refers to the way that you distinguish or inflect your words. We use tone to express emotion, emphasis, contrast, and other features of our speech. Your tone tells your audience how you are feeling about the words you say. Good intonation lets others see your attitude and your enthusiasm for your subject, and demonstrates that they are consistent.
Which do you prefer: monotonous or melodious? Do your words come out pleasant and energetic, or lifeless and wooden? Think in terms of friendliness and a desire to communicate with others and develop the best intonation that you can to captivate listeners to what you have to say.