A good speaking voice is essential when preparing in a PTE review center . You should not take your voice for granted because this is your weapon during your reviews. After all, the state of your voice can either make or break your performance in your Speaking test. The vibration of your vocal cords produces the sound of your voice. When you are not speaking, your vocal cords open so you can breathe. The moment you speak, a series of movements in your vocal region that produce vibrations creating sounds. As for the different pitch in voices, this depends on the size and shape of a person’s vocal cords.