When a child is hard to understand, parents are often told that their child has a “speech sound disorder.” But this term can feel confusing, especially when different words are used, such as articulation disorder, phonological disorder, phonological processes, dysarthria, or childhood apraxia of speech.
These conditions can sound similar because they all affect how clearly a child speaks. However, they are not the same. Understanding the difference can help parents know what their child may be experiencing and why speech therapy can look different for different children.
What is a speech sound disorder?
A speech sound disorder is an umbrella term. It refers to difficulties producing, using or organising speech sounds in a way that affects how clearly a child is understood. The American Speech-Language-Hearing Association (ASHA) describes speech sound disorders as difficulties with speech sound perception, motor production, or the phonological representation of sounds and sound patterns.
For example, a child may have difficulty making a sound clearly, such as producing the ‘s’ sound. Another child may be able to make a sound but have difficulty using it correctly in words, such as saying “tat” instead of “cat.” Some children may have broader difficulties organising speech sounds and sound patterns, which can make their speech harder to understand. Some children have one main type of difficulty. Other children may have a mixed profile.
Today, four types of speech sound disorders will be discussed:
Articulation Disorder,
Phonological Disorder,
Dysarthria,
Childhood Apraxia of Speech.
Articulation disorder: difficulty making a particular sound
An articulation disorder means a child has difficulty physically producing one or more speech sounds clearly. Currently, there is no known medical or physical cause for articulation disorder, and it is therefore called an idiopathic or functional speech sound disorder.
A child may produce a sound in a distorted or unclear way, such as saying the ‘s’ sound with the tongue pushed forward or to the side, resulting in it sounding ‘slushy’. They may know that they want to say “sun,” but their tongue placement for ‘s’ may not be accurate yet.
Articulation therapy often focuses on helping the child learn where to put their tongue, lips, jaw and airflow.
Phonological processes: patterns in the child’s sound system
Phonological disorders are error patterns in the child’s speech sound system that are atypical or persist longer than they should as the child ages. Like articulation disorder, phonological disorders have no known medical or physical cause and are therefore considered idiopathic or functional speech sound disorders.
Young children often simplify or change adult words while their speech is developing. These differences in speech patterns are called phonological processes. Many of these patterns are considered a normal part of a child’s development that the child will eventually grow out of. However, when these patterns persist for longer than expected, or when unexpected patterns outside of the normal developmental patterns appear, a child may need support. This is when we classify a phonological process as a phonological disorder.
For example, saying ‘r’ as ‘w’, such as saying “wed” for “red” or “wabbit” for “rabbit”, may be developmentally appropriate for a three-year-old child. However, if this pattern is still present when the child is seven years old, it may be considered delayed and may indicate a phonological disorder.
Some examples of other phonological processes include:
· Fronting
The child says a sound made at the back of the mouth as a sound made at the front of the mouth.
Example: “car” becomes “tar”; “go” becomes “do.”
· Final consonant deletion
The child leaves off the final sound in words.
Example: “cat” becomes “ca”; “dog” becomes “do.”
· Cluster reduction
The child simplifies consonant blends.
Example: “spoon” becomes “poon”; “blue” becomes “boo.”
Phonological therapy often focuses on helping the child understand that sound changes can change meaning. For example, “key” and “tea” are different words. Therapy may use activities such as minimal pairs to help reorganise the child’s speech sound system.
Childhood apraxia of speech: difficulty planning speech movements
Childhood apraxia of speech, often called CAS, is a motor speech disorder. It is not caused by muscle weakness. Instead, the child has difficulty planning and programming the precise movements needed for speech.
In simpler words: The child knows what they want to say, but their brain has difficulty sending the correct movement plan to the mouth.
A child with CAS may show:
Inconsistent errors, where the same word may be said differently each time.
Difficulty with vowels as well as consonants.
Difficulty moving smoothly from one sound or syllable to the next.
Unusual rhythm, stress or intonation.
More difficulty with longer words or phrases.
Visible searching or “groping” movements.
Better accuracy with some practised words, but difficulty using them flexibly.
Therapy for CAS is usually motor-based, involving frequent practice of meaningful words and phrases, with carefully adjusted visual, verbal and tactile cueing to help the child learn accurate speech movements.
Dysarthria: Difficulty executing speech movements
Like CAS, dysarthria is a motor speech disorder. However, the difficulty is different.
In dysarthria, the brain has successfully planned the speech movements, but the muscles that carry out those movements are not working as efficiently because of a range of reasons such as weakness, reduced coordination, abnormal muscle tone or reduced range of movement. ASHA distinguishes dysarthria (a motor execution disorder) from CAS (a motor planning/programming disorder).
Children with dysarthria may have speech that sounds:
Slurred
Quiet
Slow
Breathy
Monotone
Less precise
However, please note that the symptoms of dysarthria may vary depending on the underlying condition that causes the muscle differences.
Conclusion
Speech sound disorders are not all the same. Some children have difficulty making a particular sound. Some children use patterns that affect many sounds or word shapes. Some children have difficulty planning the speech movements.
A speech pathologist can help identify what is making your child’s speech unclear and develop a therapy plan that matches your child’s needs.
References
American Speech-Language-Hearing Association. (n.d.). Childhood apraxia of speech. ASHA Practice Portal. Retrieved July 14, 2026, from https://www.asha.org/practice-portal/clinical-topics/childhood-apraxia-of-speech/
American Speech-Language-Hearing Association. (n.d.). Speech sound disorders: Articulation and phonology. ASHA Practice Portal. Retrieved July 14, 2026, from https://www.asha.org/practice-portal/clinical-topics/articulation-and-phonology/
If you are concerned about your child’s speech, speak with our team at Little Birds Allied Health today.
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