Speech Sound Errors

In my "The Speech Staircase" post, I reference phonological difficulties and motor speech difficulties. In today's post, I will go into more depth about the different types of speech sound errors, particularly as they pertain to children: Phonological, Articulation, and Motor Speech.

Phonological Errors

Children who present with phonological errors are able to produce the sound(s), but struggle with the rules on when to use them. These tend to follow a pattern. For example, a child may be able to say the letter /k/, but say "tar" instead of "car". In the table below, you will find examples of phonological errors and the ages at which they are expected to resolve:

Individuals who present with phonological speech errors may present with only one pattern of error or multiple. These patterns can also sometimes overlap in the same word. For example, a child might say "diwaf" for "giraffe", demonstrating both stopping of the "dje" sound and gliding of the "r". Regardless of how many processes are present, if a child's speech errors follow these rules, they are generally classified as having phonological speech difficulties.

Articulation Errors

Articulation errors occur when the child struggles with the production of the sound, regardless of the context in which it is found. The child may be unable to produce the sound or produce it incorrectly (distortion). The Cleveland Clinic describes children with articulation errors as having difficulty with the coordination of the motor functions required for speech. This may present with difficulties coordinating the lips, teeth, tongue, palate, and/or lungs. Examples of articulation errors are lisps (distortion of the /s/ sound) or children who produce a /w/ sound instead of an /r/ sound. Some speech substitutions may be considered an articulation error in some dialects and not others. For instance, in Canada, substituting /f/ for “th” (e.g. saying “fumb” for “thumb”) is considered an articulation error. In some British dialects (e.g. Cockney), this is considered a dialectal difference and not an articulation error.

Motor Speech Difficulties

According to Caruso and Strand (1999), "traditionally, motor speech disorders in both children and adults has been divided into those that result from deficits in planning and programming movement (apraxia of speech) and deficits in executing movement for speech (dysarthria)." Motor speech difficulties can be acquired (i.e. as a result of a traumatic brain injury) or developmental (i.e. not the result of an injury, but rather something the child is born with). For the sake of this blog post, we will stick to developmental motor speech difficulties.

Apraxia

The literal translation of apraxia, from Greek, is the inability to do. Prosje (2011) described apraxia as “the complete inability to perform learned purposeful movements and is unrelated to impaired motor strength, coordination, comprehension, or sensation”. Dyspraxia refers to an impaired or abnormal ability to complete these movements. In truth, apraxia and dyspraxia are often used interchangeably in the field of speech therapy. While apraxia and dyspraxia are used to refer to any movements of the body, for the purpose of this blog, I will use “apraxia” to refer to an impaired or abnormal ability to plan and program the movements required for speech.

When describing this to parents, I explain that the child knows what they want to say, but that the message gets scrambled on the way to the lips. What ends up coming out of their mouth doesn’t sound anything like what they had intended. While some children with motor speech difficulties may also have comprehension difficulties, many do not. Children can become very frustrated because they know what they want to say, and they know that they are not being understood. When working with these children, it is so important to remain positive and highlight the strengths of the child. It is important to remember that the child is not being silly or deliberately making these errors. They are trying their best and they should not be reprimanded if their speech is unclear. So what might apraxia of speech look like in children? They may:

• distort their vowels

• have unusual patterns of errors

• demonstrate inconsistencies across multiple productions of the same word

• demonstrate trial and error when repeating, or “groping” (i.e. reaching for an articulatory position)

• they may demonstrate difficulties with control of their jaw, their lips, their tongue, their palate, or their breath support

  • this may look like:

    • clenching the jaw or opening the jaw too wide during speech

    • jaw sliding from side to side or front to back

    • difficulties with rounding (pucker) or retracting (smile) lips

    • inappropriate tongue placement

    • insufficient breath support

    • trouble with appropriate voicing

    • etc.

• they may show increased speech errors with increased word/sentence length and complexity

How does this differ from articulation errors? Articulation errors are errors at the sound level, while motor speech errors are difficulties with movement patterns. It is my personal opinion that articulation errors and motor speech errors are on a spectrum, with articulation being on the milder side of the spectrum and motor speech errors being on the more severe side of the spectrum.

Dysarthria

Defined by Caruso and Strand (1999) as deficits in executing movement for speech. This is often due to variations in muscle tone, strength, or speed. Children with dysarthria may:

• be hypernasal

• produce imprecise consonants

• distort their vowels

• demonstrate difficulties with controlling their rate of speech

• demonstrate difficulties with breath support and loudness

A good example of this is individuals with Down Syndrome, who are born with low muscle tone and a large, protruding tongue, which results in imprecise consonants and reduced clarity of speech. Children with dysarthria do not struggle with the programming and planning of speech sounds, but instead with the execution of these sounds.

Mixed

To muddy the waters, some children can present with a mix of any of the above. It can sometimes be difficult to determine the nature of the errors in such cases. It is why it's important to understand that one size does not fit all and each child requires an approach that will suit their strengths and needs. Some children benefit from visual cues (seeing mouth movements, using cue cards, etc.), while others benefit from tactile cues (using clapping, hand motions, PROMPT™, etc.), or verbal cues (prolonging vowels, slowing rate of speech, specific feedback, etc.). Many children benefit from a combination of approaches.

The Takeaway

There are three categories of speech sound errors: 1. Phonological errors, where the child can produce the sound, but struggles to use it correctly in syllables, words, and phrases; 2. Articulation errors, where the child struggles with the production of the sound, regardless of the context; and 3. Motor speech errors, which are divided into two categories: Apraxia and Dysarthria. Apraxia is defined as difficulty with the planning and programming of the movements required for speech; dysarthria is defined as difficulty with the execution of the movements required for speech. A child may present with one or many speech sound errors. It is important to work with a Speech-Language Pathologist who will assess your child and can find the best approach to suit your child’s strengths and needs. In all cases, early intervention and therapy is best.

References

1. Suffolk Centre for Speech: https://www.lispeech.com/phonological-processes-at-what-age-should-they-be-suppressed/

2. ASHA: https://www.asha.org/practice-portal/clinical-topics/articulation-and-phonology/selected-phonological-processes/

3. https://therapyworks.com/blog/language-development/phonological-processes/phonological-processes/

4. The Cleveland Clinic. https://my.clevelandclinic.org/health/diseases/23454-articulation-disorder

5. Caruso, A.J. & Strand, E. A. (1999). Motor Speech Disorders in Children: Definitions, Background, and a Theoretical Framework. In A. J. Caruso & E. A. Strand (eds.), Clinical management of motor speech disorders in children (p. 13). Thieme Medical Publishers, Inc.

6. Prosje, M.A. (2011). Developmental Apraxia. In: Goldstein, S., Naglieri, J.A. (eds) Encyclopedia of Child Behavior and Development. Springer, Boston, MA. https://doi.org/10.1007/978-0-387-79061-9_815