For bats as well as humans, trills are a difficult vocal exercise; male birds will often produce them to show off their vocal acumen.

We start with rhythm games and vocal exercises, silly things to relax them.

The vocal exercises were a more solitary pursuit.

And he hasn't yet done the day's vocal exercises which he says are essential to keep the voice in good order.

Individuals can develop their voices further through the careful and systematic practice of both songs and vocal exercises.