A speech sound disorder is when mistakes are consistently made in the pronunciation of words. There are 2 major types of speech sound disorders: Articulation disorders and phonological disorders.
An Articulation Disorder is when someone makes mistakes in pronouncing individual sounds that make up words, at an age by which time these sounds should have been mastered. Articulation disorders can be found in both children and adults. An adult may have a persistent issue from childhood, or may develop the disorder due to a stroke or head injury.
There are 4 major categories of articulation errors:
- Substitutions: (most common) This occurs when one sound is erroneously used instead of another sound. For example “wain” for “rain”, in which “w” is substituted for “r”.
- Omissions: This occurs when a sound is omitted from a word. This most commonly occurs at the beginning (example: “og” instead of “dog”) or at the end of a word (example: “cu” instead of “cup”).
- Distortions: This occurs when a sound comes out distorted, such as “thoda” instead of “soda” produced by someone with a lisp. Distortions are usually caused by poor oral motor skills.
- Additions: This error occurs when a sound that shouldn’t be in a word is added. For example, “dolla” for “doll”.
It is quite normal for young children to make mistakes in their speech. These mistakes are only classified as an articulation disorder when they continue past the age at which most children have already mastered that specific sound.
Sound Mastery chart:
| Sound | Expected Age of Mastery |
| /p,b,m,n,t,d,w,h/ & vowels | 2-3 years |
| /k,g,f,ng,y/ | 3-4 years |
| /s,z,l,v,sh,j,ch / | 4-5 years |
| /r,th,zh/ | 7-8 years |
It is also important to note that if someone speaks more than one language, they may speak English with an accent. Accents are a normal component of language, and as such are not considered to be a language disorder. An SLP can provide accent reduction services if the client wants to minimize their accent.
What causes speech sound disorders?
In many instances of speech disorders, it is difficult to pinpoint an exact cause. A child may not have learned to produce certain sounds correctly or learned the “rules of speech sounds” on their own. Many such children do develop proper speech sounds over time. However, if they are not developing typically, an SLP can usually help the process `move along`.
Some speech sound errors may also result from structural/physical issues, such as:
- A hearing loss
- A developmental disorder (PDD-NOS, Autism)
- Genetic syndromes (Down syndrome or Angelman syndrome)
- A short lingual frenum
- Neurological disorders (Apraxia, Aphasia, Cerebral Palsy)
Treatment
An SLP can provide treatment to improve the articulation of specific sounds by:
- Showing how to make the sound correctly
- Teaching the client how to recognize which sounds are correct and incorrect
- Demonstrating how these sounds apply in “everyday words”
- Setting up an at home practice program using handouts and apps