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Speech-Language Services

Speech Sound and Motor Speech

Children and adults with speech sound disorders have difficulty producing certain sounds and words clearly, which may make their speech hard to understand. The Eckelmann Taylor Speech and Hearing Clinic at Illinois State University provides expert care for articulation and phonological disorders, as well as motor speech disorders. 

Articulation and Phonological Disorders

Individuals who have articulation disorders have difficulty producing isolated sounds. They may have difficulty positioning the articulators – lips, tongue, teeth, jaw – in the correct place to make specific sounds. These errors can include the omission, distortion, or substitution of one sound for another sound.

Phonological disorders typically impact preschool children and are language-based difficulties with producing a whole group of sounds. For children with phonological disorders, they are typically able to make the oral motor movements necessary to produce sounds, but have difficulty understanding the sound system and speech rules of language.  The causes of articulation and phonological disorders are largely unknown.


Apraxia is a motor speech disorder that occurs when the brain is unable to process the movements necessary to produce speech.  Apraxia of speech can also be called childhood apraxia of speech (CAS) when diagnosed in children.  It is similar to apraxia in the adult population in that these children know what they want to say but cannot plan and sequence the oral movements.  People with apraxia may exhibit difficulty producing vowel sounds, have inconsistent sound errors and difficulty imitating others oral movements. Stroke, traumatic brain injury, and other neurological diseases can cause apraxia of speech in adults. For children with CAS, etiologies are largely unknown.


Dysarthria is another motor speech disorder that can affect a child’s or adult’s ability to speak clearly. Dysarthria occurs when the muscles of the mouth, face, or respiratory system needed to produce speech have weakened. For both age groups, symptoms of dysarthria include slurred, inconsistent speech that may sound robotic or choppy.

Similar to apraxia, dysarthria may be the result of a neurological impairment. Common neurological impairments that cause dysarthria are stroke, brain injury, Parkinson’s disease, ALS, and Multiple sclerosis. Dysarthria can also result from conditions that produce facial paralysis and muscle weakness.


Assessment and treatment

The Eckelmann-Taylor Speech and Hearing Clinic is highly qualified to treat individuals seeking services for all speech disorders. Standardized assessments and speech samples assist in determining the type and severity of the speech sound disorder.  Experienced speech-language pathologists and graduate student clinicians conduct these evaluations for disorders of articulation, phonological disorders, apraxia and dysarthria. They then collaborate with clients to develop personalized intervention plans focused on improving the individual’s speech intelligibility.


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