This is a disorder that affects the sound of speech, as well as articulation. The disorder typically involves the deformation of the pronounced sounds caused by an impaired function of the uvula, or by a decreased volume of resonation cavities. The symptom is usually increased or decreased nasality. Decreased nasality is a result of a decrease in the volume of the resonation cavities, which in childhood is usually caused by a swelling of the adenoid, or by chronic colds.