You may have noticed that young children often misproduce certain sounds. Many children produce some sounds differently than what we may expect. It is very common for young kids to swap out one sound for another, or to have a little difficulty getting one sound just right. This is a normal developmental process for children; as they are expanding the range of sounds that they can say, some sounds will come earlier than others. For some children, though, the process of speech sound development may not follow a typical trajectory, because of a speech sound disorder.
A speech sound disorder is a broad category of that includes several types of communication disorders which affect the perception or production of sounds. Difficulty in speech production often results in impaired intelligibility, or how well someone can be understood. Intelligibility is often rated as a percentage. For example, a parent may say that they can understand about half of what their child says. We would say that this child is about 50% intelligible to a familiar listener.
Types of Speech Sound Disorders
There are several distinct types of speech sound disorders, including phonological disorders, articulation disorders, and motor speech disorders. Each of these types of disorders has a different etiology, and treatment approach. Phonological and articulation disorders are two of the most frequently occurring types of speech sound disorders in children. When a child has a phonological disorder, this means that they are having difficulty producing specific sounds, and substitute certain sounds for others. For example, many young children may produce the sound “d” in place of “g”, resulting in a word like “dog” being produced as “dod”. These types of substitutions are consistent, and make up what we refer to as phonological processes.
Articulation disorders are similar to phonological disorders, in that certain sounds are produced incorrectly. The main difference, though, is that articulation disorders do not involve sound substitutions, but rather sound misarticulations or distortions. In other words, certain sounds are produced slightly off-target, but they are not being substituted by other sounds. For example, a child who has difficulty producing clear “s” sounds would likely be identified as having an articulation disorder.
Motor speech disorders are a type of speech sound disorder that result from difficulty coordinating the motor movements associated with the articulators. Childhood apraxia of speech (CAS) is a common type of pediatric motor speech disorder. Children diagnosed with CAS often have difficulty consistently producing speech sounds, resulting in reduced intelligibility. For more information about CAS, please visit the American Speech-Language Hearing Association website.
Speech Sound Development
As children are learning the sounds of their language, they will often have limited intelligibility simply because they have not yet acquired all of the sounds they need to be fully understood. For every language in the world, there is typical trajectory of development. In other words, sounds are acquired in the same order, and within the same range of time for all children learning that language. For English, the following chart shows at what ages specific sounds are acquired.
The causes of speech sound disorders are often related to other underlying conditions, but it is possible that there may be no clear reason for the disorder. Some conditions that may result in a speech sound disorder include the follow:
- Developmental disorders, such as autism or developmental delay
- Brain damage or trauma, like cerebral palsy
- A genetic syndrome, like Down syndrome
- Hearing loss
- A history of ear infections
Treatment for speech sound disorders should always include a licensed speech-language pathologist. There are a variety of different approaches and treatment techniques. Each treatment plan is highly individualized, and your child’s speech pathologist will determine the most appropriate approach. It is important to note that speech sound disorders have little to do with muscle strength. Doing mouth or tongue exercises to increase strength will do nothing to support the development of improved intelligibility.
If you are concerned about your child’s intelligibility, you should consult with a speech-language pathologist. They will conduct an evaluation to determine the degree to which a speech sound disorder may be causing difficulty with speech production. Although you may be tempted to wait it out, it is best to consult with someone who is knowledgeable about pediatric speech sound development. A speech-language pathologist can offer guidance about the best course of action if treatment is recommended.
José A. Ortiz, M.A., CCC-SLP