Cleft palate speech is characterized by a pronounced nasality of all the vowel sounds, an inability to pronounce the dentals t and d, the labials p and b, the palatals k, hard g and hard c and an incorrect pronunciation of the labiodentals f, v, l, r, and the sibilants s and z.
There are several types of cleft palate: a cleft in the soft palate, a cleft in the hard palate, a cleft in both or a cleft in the upper lip. This last condition is known as harelip and is frequently associated with the other types of cleft palate.
MECHANISM OF SPEECH FAILURE
The speech defect is due to a failure of function on the part of the palate. The soft palate and its prolongation, the uvula, serve to close up the posterior passage to the nose during phonation. This closure takes place in the production of