We are all aware that our respiratory system plays a significant role in the production of nearly all speech sounds;It is The basic source of energy.In this respect,I will first try to explain how these sounds are being produced when talking.More specifically ,in exhalation,the air coming from the lungs –pulmonic air as a technical term- goes up passing through the trachea or the windpipe into the larynx, at which point it must pass between two small muscular folds called the vocal folds( or the vocal cords :those elastic folds of membranous tissue in the larynx forming a slit across the glottis in the throat, and whose elasticity enables them to vibrate when the air-stream passes through to produce the voice.If the vocal folds are apart (as yours probably are right now in normal breathing), the air from the lungs will have a relatively free passage into the mouth,with no vibration in the vocal folds; However, if there is only a narrow passage between them, the air stream will set them vibrating. Voiced sounds therefore are those speech sounds produced when the vocal folds are vibrating , as opposed to voiceless sounds in which the vocal folds are apart without vibration. For instance we have the sound /p/ and /b/ which both are sharing the same place of articulation-bilabial-,but the only difference between them is voicing./P/ is said to be voiceless as opposed to /b/,and you can feel this vibration by placing your fingertips against the larynx.Voicing is really important in distinguishing sounds. Consider these pairs of words : pan, bat; sight, zero; tide, dawn. The first consonants in pan,sight and tide are voiceless; in the second words of each pair ,bat,zero and dawn,respectively,are voiced.
- Mohamed Amin Ghoues