Complex sentence: The difficulty in articulation does not occur due in the planning the motor movement, as AOS does, but rather is caused by the inability or weakness of the muscles in the mouth, face, and respiratory system.
Split into simpler sentences: The difficulty in articulation does not occur due in the planning the motor movement, as AOS does. Instead, Dysarthria is caused by the inability or weakness of the muscles in the mouth, face, and respiratory system.