Cleft palate, PAL iht, is a birth defect in which there is a split in the roof of the mouth. Many people born with a cleft palate also have a cleft lip--a split through the upper lip. Cleft lip--with or without cleft palate--occurs in about 1 out of every 700 births. Cleft palate alone occurs in about 1 out of every 2,500 births.