The word “palate” has taken on a variety of meanings in English, most of them having to do with taste in food or drink. Cleansing one’s palate, for instance, is a common saying for clearing the taste out of one’s mouth; similarly, something that is unpalatable is not suitable for eating. The anatomical purpose of the palate has little to do with taste, however. The palate is essentially the roof of the mouth, divided into soft and hard portions. It separates the oral cavity of the mouth from the nasal cavity and the sinuses, and creates a barrier between the internal workings of the nose and mouth.
There are two parts of the palate in humans and most vertebrates. The hard palate is the largest part, and sits directly above the tongue, between the top row of teeth. It is made primarily of bone. It is a foundational part of the oral cavity, and its shape often dictates how well the top and bottom teeth fit together.
The soft palate, by contrast, is fleshy and malleable. Also called the velum, it is located behind the hard palate, almost to the throat, and its main function is to act as a physical barrier between the oral and nasal cavities. While the hard portion separates the nose from the mouth with bone, the throat and nasal cavities are still connected. The soft portion restricts and closes that connection when swallowing food or drink. Without the velum, foodstuffs destined for the stomach could get diverted into the nasal cavity.
Speech sounds are also heavily influenced by the velum, as the velum helps control the amount of air in the mouth and vocal tract. Humans form sounds and words in the vocal tract, which is a collective name for the larynx, pharynx, oral cavity, and nasal cavity. A velum that is under-formed or poorly formed is often to blame for nasal-sounding speech. Velum abnormalities have also been blamed for various speech impediments, such as stuttering, although the medical causes of most speech impediments are not definitively known.
Both hard and soft portions form in fetuses during the first trimester of gestation. In a small percentage of people, estimated in 2010 to be one in seven hundred, the palate does not fully fuse. This leaves a gap, or cleft, in the middle of the mouth that commonly extends through the lip and nose. Unfused palates are commonly referred to as a cleft palates or cleft lips, and afflict people of all races in all countries.
Many scientific studies have linked cleft palates to a deficiency of folic acid during pregnancy. Adequate folic acid levels do not guarantee proper palate formation, however, and the condition is not one that can be prevented. Cleft palates can be repaired with surgery. Surgery can restore the physiological role of both hard and soft palates, and usually also corrects any facial abnormalities caused by the cleft.