What Are the Causes of Articulation Disorders in Children?
Articulation disorders are generally the largest percentage of a speech & language pathologist's schedule. These disorders may range from mild to severe, meaning that the intelligibility of a child's speech may range from poor to excellent. There are many underlying reasons why some children have these deficits.
First, some children have hearing impairments. The problem we see most frequently is recurrent otitis media, or middle ear infection. Children who suffer from recurrent otitis media have fluid in their middle ear that impedes the transmission of the acoustic signal and is described as feeling like "hearing sound through water." One other problem that these children have to deal with is hearing thresholds that fluctuate. Even though this kind of hearing loss will not be a severe one, imagine you are a little child and you are learning language for the first time. Sounds are not only distorted, but distorted in ways that vary over time. So it is not just hearing thresholds that vary but the actual perception of sounds vary. Remember, we adults have a point of reference but, to a child, sounds and words are all new. If a child keeps hearing a sound differently, s/he will very likely not learn to say it correctly. Some children exhibit auditory perceptual deficits in the absence of a hearing loss. These children, too, have difficulty with speech sound production, ostensibly because they don't hear sounds and words the way they were spoken.
A hearing loss that is the result of a problem in the inner ear will also affect how a child learns to say sounds. These are called sensorineural hearing losses and are the result of a problem in the cochlea and/or the auditory nerve. These hearing losses tend to be more severe, resulting in an even more severe deficit in speech sound production. In our April 2011 issue, we featured an article on cochlear implants, a revolutionary treatment for sensorineural hearing losses. Children with severe hearing losses generally require years of speech therapy to produce speech sounds correctly.
Other times, articulation disorders are the result of problems in the structure of the articulators. For example, some children are born with a cleft lip, palate and/or soft palate. Some children are born with ankyloglossia or tongue-tie as it is more commonly known. In this case, the membrane that attaches the tongue to the floor of the mouth (called the frenulum) is too short. Although most of the time, children seem to be able to adapt to this restriction of movement, the condition may be treated medically by clipping the frenulum. Other structural problems which can affect speech sound production may include enlarged tonsils and adenoids and a high arched palate. Missing front teeth may impact the development of the /s/ and /z/ sounds.
When speech pathologists describe the function of the articulators, that refers to how the lips, tongue and jaw move. Movements should be symmetrical; the right and left sides of the face should look the same. In addition, the articulators should be able to move separately. If these conditions are not met then specific speech sounds will be distorted. If there is a generalized weakness in speech movements, the resulting speech will be slurred and unclear. If the child has retained an immature swallow pattern, s/he will most likely have difficulty with the /s/ and /z/ sounds, as well as other sounds that require tongue tip elevation. Unless the speaker is saying the /th/ sound, the tongue should always be inside the oral cavity.
Rarely, but occasionally, a child may exhibit an apraxia of speech. This condition is neurological in origin and results in difficulty in initiating, planning and executing speech movements. Generally, children with apraxia of speech are quite unintelligible and require intensive speech therapy. They also often exhibit concomitant learning difficulties such as dyslexia.
Finally, there are functional articulation disorders. These disorders, which are a large percentage of those with articulation problems, simply have no obvious cause. The important thing to remember, however, is that whatever the cause, speech therapy is going to give these children the optimal chance at producing sounds correctly. Overwhelmingy, when children complete a course of speech therapy, they leave with perfect articulation.