Articulation Disorder Causes
You might wonder why some 3-year-olds have perfectly clear speech, while some older kids have speech that is difficult to understand. One reason could be an articulation disorders which can occur as the result of some of the conditions below. In most cases, children with articulation disorders are typically developing in all other areas.
Some causes of articulation disorders include:
Permanent or occasional hearing loss. It is very important for children to hear clearly during the critical learning ages of birth to 3 years. A child with
even a slight hearing loss, such an inability to hear high-pitched sounds, might not hear some aspects of the native language (e.g., the /f/ and /s/ in English are high-pitched).
Imagine hearing a conversation without hearing all of the sounds spoken at the beginning, middle, or end of words; the speech signal would not be able to provide a complete sample of normal speech. Yet, a young child is expected to learn from that “incomplete” speech sample. A slight hearing loss could deprive the child of the opportunity to hear how to correctly produce and master the sounds.
There are various types and severities of hearing loss. Some children are born with profound loss, while others may develop a hearing loss after repeated ear infections (otitis media). The SLP will ask about your child’s history of ear infections, and your child may be referred to an audiologist for a complete hearing evaluation. It is important to rule out any medical conditions prior to diagnosing and treating speech and language disorders.
Physical malformations. Articulation disorders can result from virtually any change to the normal anatomy of the oral cavity (mouth, jaw, and throat). Ma
ny children are born with or acquire physical malformations, including: cleft lip or palate, in which the bone and/or tissue of the upper portion of the mouth does not form correctly; ankyloglossia, or tongue tie, in which the tongue is “tied” to the bottom of the mouth by a short string called the frenulum; and dental malocclusions, in which the teeth are not properly aligned.
When an articulator is altered by a malformation, the child’s speech is likely to be affected, sometimes in predictable ways. For example, SLPs can often identify the speech of a child with cleft palate from an audio-recording only, because the cleft allows air to escape into the nose, resulting in hypernasalspeech.
Neuromuscular disorders. Speech articulation is likely to be affected by disorders that affect the muscular system, such as cerebral palsy (a non-progressive
movement disorder resulting from brain injury) and muscular dystrophies (a progressive disease in which muscle function declines as a result of defective genes).
Some muscular disorders affect the speech production areas of the brain specifically and result in a motor speech disorder called dysarthria. A person with dysarthria produces speech that may be slurred, too slow or too rapid, abnormal in pitch and rhythm, and generally difficult to understand.
Developmental delays and disorders. A variety of developmental disorders, including those that begin before birth and those that are acquired after birth due to injury or infection, can cause poor articulation skills. Some developmental disabilities result from maternal infections during pregnancy, prenatal exposure to toxins (e.g., fetal alcohol syndrome), gene disorders (e.g., Down syndrome), and premature birth.
Some developmental disorders have no known cause, such as autism spectrum disorder, which affects many areas of a child’s development including speech. General developmental delays, including intellectual disabilities or learning disabilities, may also result in poor speech skills.
When evaluating a child’s articulation, an SLP may identify symptoms of a developmental disorder known as apraxia of speech (also known as childhood apraxia of speech, or CAS). CAS is a motor speech disorder that results from poor motor planning from the brain to the articulators (e.g., lips and tongue). The resulting incoordination often has significant effects on the child’s ability to produce even simple sounds and words.
No known cause. As with many speech and language delays and disorders, articulation disorders do not always have a clear cause. It is important for parents to realize that some children are simply not as skilled in coordinating speech movements; they may excel in many other areas though.
The cause of an articulation disorder, if known, is an important factor in developing a child’s treatment plan in therapy. The SLP should be aware of any medical diagnosis that might affect how much progress a child should be expected to make in remediation of the articulation disorder.