Why does the incomplete development of hard palate cause nasality?

An incompletely developed hard palate, or a cleft palate, can cause nasality because it allows air and sound to escape through the nose during speech.

Normally, the hard palate separates the nasal cavity from the oral cavity, creating a closed space that allows for the buildup of air pressure necessary for the production of certain speech sounds, such as consonants.

When the palate is incomplete, this closed space is disrupted, and air leaks through the nose, resulting in a nasalized quality to speech.

Additionally, the incomplete palate can affect the resonance of the vocal tract, altering the overall sound of speech and making it difficult for others to understand.