Your most valuable piece of equipment as a cheerleader is... your voice, of course. I recently took a class for teachers and school professionals on crisis intervention and they taught us about using our voices to defuse potentially volatile situations with our voices. They explained that "non-verbals" doesn't just refer to facial expression and body language- some of the most powerful part of communication is not what you say, but how you say it. In other words, it's not the words, but the non-verbal vocal qualities that can calm, intimidate, or in the case of a cheerleader- invigorate.
The instructors, both school psychologists explained to us how important 3 aspects of our voices are.