Which statement best distinguishes a motor-speech disorder from a phonological process disorder?

• A. Inability to perform voluntary oral movements
• B. Difficulties in range of phonemes but can move mouth normally
• C. Pattern of errors limited to phoneme substitutions
• D. Errors are consistent across contexts

Answer: (B)

This item tests how to tell apart a problem with moving the speech muscles from a problem with how sounds are organized in the brain. A motor-speech disorder affects the actual execution of movements needed to produce speech—the articulators—so you’d expect issues tied to motor control. If someone can move their mouth normally, that signals the motor system is okay, and the difficulty lies in the sounds’ organization rather than in the movement itself.

The statement that describes difficulties with a wide range of phonemes while the mouth can move normally fits that distinction. It indicates the person’s motor system works, but there’s a limitation in the phoneme repertoire or in the learned patterns of sounds, which is characteristic of a phonological process disorder rather than a motor-speech issue.

So, focus on the idea that intact movement with limited phoneme variety points to phonological processing differences, not motor planning or execution.