Intelligibility is a measure of how well speech can be understood. Everyone has dysfluencies from time to time. Everyone has dysfluencies in their speech. Apraxia Apraxia is a motor disorder in which volitional or voluntary movement is impaired without muscle weakness. The ability to select and sequence movements is impaired.
Oral apraxia affects one ability to move the muscles of the mouth for non-speech purposes.
Someone with oral apraxia would have trouble coughing, swallowing, wiggling their tongue or blowing a kiss when asked to do so. As everyone's voice is unique it is difficult to define a normal voice. A normal voice is pleasant sounding and has age and sex appropriate pitch and loudness. When a voice is not pleasant sounding, is too loud or too soft or is too high or low for one's gender, a voice problem may be present. Damage to the brain can be caused by stroke, tumour or head injury.