Speech Sound Disorders In Children: What Causes Them

Quick Summary

Speech sound disorders are among the most common conditions addressed by speech-language pathologists in children. They include articulation disorders, phonological disorders, childhood apraxia of speech, and dysarthria. Each has a distinct profile and requires a different therapeutic approach. According to ASHA, nearly 8% of children ages 3-17 have had a disorder related to voice, speech, language, or swallowing. Early identification and the right type of speech therapy make a significant difference in outcomes.

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It is entirely normal for young children to mispronounce words. A two-year-old who says "wabbit" for "rabbit" or "pasketti" for "spaghetti" is not showing a speech disorder. They are showing the predictable, developmentally appropriate process of a child whose speech system is still maturing. These kinds of errors are expected and resolve naturally as the child's phonological system develops.

But some children's speech errors persist beyond the age when they should have resolved, follow unusual or inconsistent patterns, or significantly affect how well the child is understood. These children may have a speech sound disorder, a term that covers several distinct conditions affecting how children produce the sounds of their language.

Speech sound disorders are among the most common reasons children are referred for speech-language services. As the American Speech-Language-Hearing Association (ASHA) notes, a child who has frequent trouble saying sounds or who is hard to understand may have a speech sound disorder. Nearly 8 percent of children ages 3 to 17 in the United States have experienced a disorder related to voice, speech, language, or swallowing.

At Innovative Interventions, our speech-language pathologists work with children in their homes across New Jersey, providing early speech intervention during the years when the impact is greatest.

What Is a Speech Sound Disorder?

A speech sound disorder is any condition in which a child consistently has difficulty producing the sounds of their language in a way that is expected for their age and background. The key word is "consistently." Occasional errors are normal. Persistent, patterned errors that fall outside the expected developmental range are what define a disorder.

ASHA distinguishes between speech sound disorders and language disorders. A speech sound disorder affects how sounds are produced. A language disorder affects how language is understood and used. Both can occur independently or together, and a comprehensive evaluation assesses both dimensions.

It is also important to note that accent, dialect, and the influence of languages other than English are not speech sound disorders. A child whose speech patterns reflect their home language or community dialect is not disordered. This distinction matters enormously for families who speak languages other than English at home and should always be accounted for in any evaluation.

Types of Speech Sound Disorders

Articulation Disorders

An articulation disorder is difficulty producing a specific sound or small set of sounds correctly. The problem is in the physical production of the sound: the child has not learned the precise placement of the tongue, lips, teeth, and airflow required to make the sound correctly.

Common examples include difficulty with the "r" sound (rhotacism), difficulty with "s" and "z" (sigmatism or lisping), and difficulty with "l." These are among the most frequently treated sound errors in speech therapy, and they respond well to targeted articulation treatment once the child's system is developmentally ready to address them.

A key feature of articulation disorders is that errors are typically consistent: the child makes the same substitution or distortion every time they attempt the sound. This consistency distinguishes articulation disorders from the inconsistency that characterizes childhood apraxia of speech.

Phonological Disorders

Phonological disorders involve systematic patterns of errors across whole classes of sounds, rather than difficulty with a single sound. The child's underlying phonological system, the mental representation of how sounds work in the language, is organized differently from typical.

Common phonological processes include:

• Final consonant deletion: Consistently dropping the last sound from words ("ca" for "cat," "do" for "dog")

• Fronting: Replacing sounds made at the back of the mouth with sounds made at the front ("tup" for "cup," "dit" for "get")

• Cluster reduction: Simplifying consonant clusters ("poon" for "spoon," "top" for "stop")

• Stopping: Replacing fricative sounds with stops ("toup" for "soup," "pish" for "fish")

Many of these processes are developmentally normal at younger ages and gradually disappear as the child's phonological system matures. When they persist significantly beyond the expected age of resolution, therapy is warranted. Phonological therapy takes a different approach than articulation therapy: rather than drilling specific sounds, it works at the level of the sound pattern to help the child reorganize their phonological system.

Childhood Apraxia of Speech (CAS)

Childhood apraxia of speech is a motor speech disorder in which the brain has difficulty planning and programming the precise sequences of movements needed to produce speech. Unlike articulation disorders, where the problem is learning a specific sound, or phonological disorders, where the problem is in how sounds are organized, CAS is a problem with the motor planning process itself.

The hallmark feature of CAS is inconsistency: the child may produce a word correctly once and very differently the next time. Other characteristics include difficulty with longer or more complex words, unusual prosody (rhythm and melody of speech), and visible groping or struggle when attempting to speak. CAS is treated through motor learning principles, specifically intensive, repetitive practice with carefully structured feedback, not through standard articulation therapy.

For a detailed look at CAS, including age-by-age early signs, visit our dedicated post on childhood apraxia of speech.

Dysarthria

Dysarthria is a motor speech disorder caused by weakness, paralysis, or poor coordination of the muscles used for speech. Unlike apraxia, where the muscles themselves are intact but the brain cannot plan their coordinated movement, dysarthria involves the muscles directly. Speech in someone with dysarthria may sound slurred, slow, soft, or breathy, and it may be consistently difficult to understand regardless of the word or context.

In children, dysarthria is most commonly associated with neurological conditions such as cerebral palsy, traumatic brain injury, or muscular dystrophy. Treatment focuses on improving intelligibility through strategies appropriate to the underlying cause and severity.

Signs and Symptoms of a Speech Sound Disorder

The following signs, relative to the child's age, may indicate a speech sound disorder:

• Being significantly difficult to understand by unfamiliar listeners at an age when most children's speech is intelligible

• Consistently omitting sounds at the beginning or end of words

• Substituting one sound for another in a way that creates confusion ("wun" for "run" across all contexts)

• Distorting sounds so that they do not match any standard production

• Producing a word differently each time it is attempted (pointing toward apraxia)

• Visible struggle, groping, or frustration when attempting to speak

As ASHA's sound acquisition chart indicates, most English-speaking children can produce the sounds m, n, h, w, p, b, t, d, k, g, and f correctly in words by age 3. By age 4, y and v are added, and most people can understand the child's speech. Errors on s, sh, ch, j, ng, th, z, l, and r may still be present at age 4 without indicating a disorder. The expected age of mastery matters enormously when evaluating whether an error pattern is a concern.

What Causes Speech Sound Disorders?

Causes vary by type of disorder:

• Neurological: Conditions affecting the brain's planning or programming of movement (CAS) or the muscles themselves (dysarthria)

• Structural: Physical differences in the palate, tongue, or other articulators. Cleft palate, even when repaired, commonly requires speech therapy. Tongue-tie may affect sound production in some children

• Hearing loss: Children who cannot hear sounds clearly may not produce them correctly. Chronic ear infections creating intermittent hearing loss are a particularly common and underrecognized contributor

• Developmental: Many speech sound disorders arise during typical development when a child's phonological system matures more slowly or differently than expected, without any identifiable underlying cause

• Genetic or syndromic: Certain genetic conditions including Down syndrome and 22q11.2 deletion syndrome are associated with speech sound disorders as part of a broader developmental profile

How Speech Sound Disorders Are Diagnosed

Diagnosis is made by a speech-language pathologist through a comprehensive evaluation. The evaluation typically includes:

• A review of the child's medical and developmental history

• Standardized assessment of speech sound production in single words and connected speech

• Analysis of the type and pattern of errors to identify the specific disorder

• Assessment of oral motor function: the strength and movement of lips, tongue, and jaw

• Hearing screening or referral for audiological evaluation if hearing concerns are present

• Observation of spontaneous speech in naturalistic play or conversation

For children under three in New Jersey, evaluations for speech sound disorders can be conducted through the early intervention program as part of a free multidisciplinary evaluation.

When Should Parents Be Concerned?

Trust your instincts, and seek evaluation if you have concerns. Specific benchmarks that warrant action include:

• Your child is not producing consonant sounds in babble by 9 to 12 months

• Familiar adults understand less than 50% of what your 2-year-old says

• Strangers understand less than 75% of what your 3-year-old says

• Your 4-year-old still makes errors on early-developing sounds like p, b, m, n, t, d

• Your child shows frustration, avoidance, or visible struggle when speaking

• A teacher, childcare provider, or another parent has expressed concern about understanding your child

How Speech Therapy Helps Children With Speech Sound Disorders

The specific approach depends on the type of disorder. For articulation disorders, therapy focuses on teaching correct placement and production of specific sounds, progressing from isolation to syllables, words, sentences, and conversation. For phonological disorders, therapy works at the level of the sound system, using contrast and pattern-based approaches to help the child reorganize their phonological representations. For CAS, motor learning principles guide high-intensity, structured practice with specific feedback.

In all cases, what happens between sessions is as important as the session itself. Our speech therapy team coaches caregivers in strategies to reinforce target sounds and patterns throughout the child's day, because generalization to spontaneous speech in real environments is the ultimate measure of success.

Can Children Outgrow a Speech Sound Disorder?

Some mild articulation errors, particularly on late-developing sounds like "r" and "th," may self-correct over time. Mild phonological processes also tend to diminish naturally as the child's phonological system matures. However, disorders that significantly affect intelligibility, or that involve patterns inconsistent with developmental expectations, rarely resolve fully without intervention.

More importantly, waiting without evaluation means not knowing which category a child falls into. An evaluation does not commit a family to a lengthy course of therapy. It provides the information needed to make a well-informed decision.

When to Contact a Speech Therapist

Any time you have a concern about how your child produces speech sounds, a speech-language pathologist can provide an evaluation and clear guidance. For children under three in New Jersey, this service is available through the early intervention program at no cost to the family.

You can also request an evaluation through our contact page at Innovative Interventions, and our team will connect you with the appropriate services in your area. Visit our FAQ page to learn more about what the evaluation process looks like for young children in New Jersey.

Frequently Asked Questions

What is the most common speech sound disorder in children?

Articulation disorders and phonological disorders are the most frequently identified. Errors involving the "r" sound and phonological processes like final consonant deletion are particularly common presentations.

Is a speech sound disorder the same as a lisp?

A lisp is a specific type of articulation disorder affecting the "s" and "z" sounds. It falls within the broader category of speech sound disorders but is one specific presentation among many.

How do I know if my child's speech errors are typical or a disorder?

The key factors are the type of error, the child's age, and the pattern of errors over time. A speech-language pathologist can evaluate your child against developmental norms and determine whether errors fall within expected variation or warrant intervention.

Can a speech sound disorder affect reading?

Yes. Phonological awareness, the ability to recognize and manipulate the sound structure of language, is strongly linked to reading development. Children with phonological disorders are at higher risk for reading difficulties, and early speech therapy can also support early literacy skills.

Is speech therapy for sound disorders done in a clinic or at home?

Both settings are used. For children under three in New Jersey, the early intervention program provides speech therapy in the home as part of its natural environment mandate. Older children may receive services at school or in a clinic setting depending on their needs and eligibility.