The first is to act as a mechanical barrier between the mouth and the nose so that what we eat and drink doesn’t leak back out through the nose.
The second is to act as a valve at the back of the throat to block the flow of air into the nose. This second function is extremely important and is necessary for feeding as an infant and for speech.
When we talk, air comes out of our lungs, travels up through the vocal cords and arrives at the back of the throat. In order to form speech sounds from that air, it then has to go to the right place – we make some speech sounds in our nose and others in our mouth. The soft palate directs the flow of air into the right place for the right sound. Most of the sounds in speech are made in our mouths, so if the soft palate has a cleft, or if it doesn’t work well, then most of the sounds that we use in speech can’t be made. See the speech section for more information.