The uvula plays an important role in the articulation of the sound of the human voice to form the sounds of speech. It functions in tandem with the back of the throat, the palate, and air coming up from the lungs to create a number of guttural and other sounds. Consonants pronounced with the uvula are not found in English; however, languages such as Arabic, French, German, Hebrew, Ubykh, and Hmong use uvular consonants to varying degrees. Certain African languages use the uvula to produce click consonants as well. In English (as well as many other languages), it closes to prevent air escaping through the nose when making some sounds, such as /b/.
In a small number of people, the uvula does not close properly against the back of the throat, causing a condition known as "velopharyngeal insufficiency" or VPI. This causes "nasal" (or more properly "hyper-nasal") speech, where a lot of extra air comes down the nose, and the speaker is unable to say certain consonants, for example producing the sound /b/ like /m/.
Snoring and sleep apnea
The uvula can also contribute to snoring or heavy breathing during sleep; having an elongated uvula can cause vibrations which lead to the snoring. In some cases this can lead to sleep apnea, which may be treated by removal of the uvula or part of the uvula if necessary, an operation known as uvulopalatopharyngoplasty (commonly referred to as UPPP, or U3P). It should be noted, however, that this operation can also cause sleep apnea if scar tissue forms and the airspace in the velopharnyx is decreased. The success of UPPP as a treatment for sleep apnea is unknown, but some research has shown 40-60% effectiveness in reducing symptoms. Typically apnea subsides for the short term, but returns over the medium to long term, and sometimes is worse than it was before the UPPP.
During swallowing, the soft palate and the uvula move superiorly to close off the nasopharynx, preventing food from entering the nasal cavity. When this process fails, the result is called nasal regurgitation. It is common in people with VPI.