Pitchness; Do you hear me?
Another voice variation is by change of pitch. Such changes is the surest way to compel attention from your audience. Ever been to an orchestra before? Throughout the orchestration, do you notice that there are times where the music reaches its crescendo and gradually decreases in its loudness. Likewise, try applying that in your speech, a time to increase your pitch and a time to decrease it. Consider the following sentence:
WHAT ON EARTH IS GOING ON? please don't scare me
Such technique would definitely compel the attention of the listeners. Imagine, if some of your audience are deep in thoughts, others whose minds are wandering somewhere, with this change to pitch would compel their attention back into reality. Moreover, in order to prevent the usual monotonous voice, such changes would definitely add varieties to your speech.
Though it's never easy at first, to change your pitch quite spontaneously, you tend to focus more on changing your pitch than your core message itself, but with enough practices you shall get over it very soon, as Calvin Coolidge said, "Nothing takes the place of persistence"