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Speech Intelligibility: How clear is your child’s speech?

Updated: Nov 25, 2020

Have you ever found it difficult to understand your child’s speech? How they articulate sounds impacts their overall clarity in speech. A Speech Language Pathologist (SLP) can help you understand if your child’s speech intelligibility is at an appropriate level for their age.

What is Speech Intelligibility?

Speech intelligibility refers to how well someone can be understood when they’re speaking. The factors that determine someone’s clarity include knowing what sounds to make and how to pronounce them, the rhythm (also known as prosody), the volume, staying on topic, formulating syntax, and more. There’s a lot that goes into our conversations without us even realizing it!

How is it Measured?

There are a variety of methods SLPs use to measure a client’s speech intelligibility. Some use their trained experience to listen and estimate the percentage of speech that can be understood. A more formalized method involves:

1) recording the client saying a list of pre-selected words/sentences

2) providing a second person with a list of similar sounding words

3) the second person will listen to the recordings and select from the list which word they think was being said.

This helps eliminate the bias that family members can have since they hear the client speak every day and might understand them better than a stranger would.

When Should My Child Be Fully Intelligible?

Ideally, as children age, their speech intelligibility should be increasing. According to data presented at the 2003 American Speech-Language-Hearing Association convention, the typical norms you want to look for in a child are:

  • 26 - 50% intelligible by age 2

  • 75% intelligible by age 3

  • 90% intelligible by age 4

By age 5, a child following the typical development norms should be 100% intelligible. Errors in pronunciation can still occur, but this just means that a stranger should have no problem understanding what the child is trying to say.

What Causes Difficulties with Speech Intelligibility?

Of course, things like background noise or hearing difficulties on the listener’s end can affect how well someone is understood. However, there are some conditions that can impact someone’s ability to communicate clearly and be understood. Here are some of the most common ones:

  • Childhood Apraxia of Speech / Developmental Apraxia of Speech

    • The brain has issues with planning movement of the lips, jaw and tongue

  • Dysarthria

    • Muscle paralysis or weakness causing slurred speech or other issues with intelligibility

  • Speech Sound Disorders

    • Replacing certain sounds, distorting them, or omitting them altogether; can be caused by hearing loss, dental abnormalities, cleft palate, etc.

  • Stuttering

How Can It Improve?

An SLP will assess a client’s situation and needs in order to determine what type of therapy is needed and how it can improve their situation. Typically, without any other underlying cause for low speech intelligibility, speech therapy itself can help the individual learn how to improve their speech.

When there is an underlying cause to the reduced speech clarity or a delay in improvement, other supportive measures can be put in place, such as:

  • Incorporating sign language, hand gestures or facial cues in speech

  • Learning to control pace and breathing

  • Introducing AAC devices

  • Working on volume and resonance

  • Developing speaker-listener communication strategies -- providing feedback or asking questions, looking for facial cues, maintaining eye contact, etc.

If you’re having any trouble understanding your child and want to schedule an assessment with an SLP, we are still providing teletherapy during these times of social distancing -- feel free to contact us with any questions!


Dolgin, E. (2019, May 11). Dysarthria. Retrieved from

Keintz, C., Hustad, K., Garcia, J., & Klasner, E. (n.d.). Speech Intelligibility: Clinical Treatment Approaches for Children and Adults.

McCleod, S., & Bleile, K. (2003). Neurological and developmental foundations of speech acquisition . American Speech-Language-Hearing Association Convention. Retrieved from

Scanlon, K. (n.d.). Is Your Child Intelligible? Retrieved from


Andalusia Speech Therapy has two Toronto speech therapy clinics and offers speech teletherapy to anywhere in the world. Contact us more for information.

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