The art of tai chi and the art of singing share many things -- discipline, regular practice, and an emphasis on the breath. But, what may surprise you, as it did me, is that the breath, as a vehicle for directing energy to the singer's stage presence, was paramount in the success of any stage production.
I have found that my vocal chords and my throat are like a canary in a cave. If they don't feel right, a cold, flu or other general cootie is generally right around the corner. Does this send panic through me as I set out to sing or act? Yes it does. Does the same issue hold true for public speaking? Yes it does.