(1) Pitch is an integral part of the human voice. The pitch of the voice is defined as the“rate of vibration of the vocal folds”. The sound of the voice changes as the rate of vibrations varies. As the number of vibrations per second increases, so does the pitch, meaning the voice would sound higher. Adult male voices are usually lower pitched and have larger folds. The male vocal folds are between 17 mm and 25 mm in length. The female vocal folds are between 12.5 mm and 17.5 mm in length.