SDD of speech and language entities

Speech Disorders / Impairments are a type of communication disorder in which normal speech is disrupted. This can mean stuttering, lisps, etc. Someone who is unable to speak due to a speech disorder is considered mute. Speech is a complex process that requires precise timing, nerve and muscle control, and as a result is susceptible to impairments. Speech disorders affect roughly 11.5% of the US population, and may be caused by a stroke, an accident or birth defect.

Classification[edit]

Classifying speech into normal and disordered is more problematic than it first seems. By strict classification,^{[citation needed]} only 5% to 10% of the population has a completely normal manner of speaking (with respect to all parameters) and healthy voice; all others have one disorder or another.

There are three different levels of classification when determining the magnitude and type of a speech disorder and the proper treatment or therapy:

1. Sounds the patient can produce
   1. Phonemic – can be produced easily; used meaningfully and constructively
   2. Phonetic – produced only upon request; not used consistently, meaningfully, or constructively; not used in connected speech
2. Stimulate sounds
   1. Easily stimulated
   2. Stimulate after demonstration and probing (i.e. with a tongue depressor)
3. Cannot produce the sound
   1. Cannot be produced voluntarily
   2. No production ever observed

Types

• Apraxia of speech

• Cluttering, a speech and fluency disorder characterized primarily by a rapid rate of speech, which makes speech difficult to understand.

• Dysarthria is a weakness or paralysis of speech muscles caused by damage to the nerves or brain. It is often caused by strokes, Parkinson's disease, ALS, head or neck injuries, surgical accident, or cerebral palsy.

• Aphasia
• Dysprosody
• Muteness is the complete inability to speak.
• Speech sound disorders
• Stuttering (AKA “Dysphemia”)  affects approximately 1% of the adult population.
• Voice disorders are impairments, often physical, that involve the function of the larynx or vocal resonance.

Causes[edit]

In most cases the cause is unknown. However, there are various known causes of speech impairments, such as hearing loss, neurological disorders, brain injury, an increase in mental strain, constant bullying, intellectual disability, substance use disorder, physical impairments such as cleft lip and palate, and vocal abuse or misuse.