The need for a voice prosthesis sets in only after a laryngectomy. Your laryngectomy might be a total or a partial one – that determines whether or not the patient would lose his/her speech permanently! The outcomes of a laryngectomy are hard to accept, and therefore, surgical experts mostly try to keep laryngectomy at the partial level. Voice prosthesis is needed to cope with the stress post the laryngectomy. This surgery leads to eating difficulties and speech problems too. Well, eating is not an all-day affair. But speaking is. The pain of not being able to make yourself understandable to others is sometimes unbearable. The Voice prosthesis is a one-way valve that is fitted inside the fistula which aids in pushing out the air from the lungs through the mouth. One needs to cover the stoma to do this. After weeks and months of practicing this, the individual is able to make himself audible to others! https://www.garnersupply.com/articles/medical-articles/voice-prosthesis-and-coping-with-the-stress-after-laryngectomy.html