A speech sound disorder occurs when a person has difficulty producing speech sounds, affecting his or her ability to communicate. Children often make mistakes as their vocabulary grows, but a speech sound disorder occurs past the age at which they are expected to know how to make the correct sounds. Sometimes, speech sound disorders continue into adulthood. Other adults develop speech problems following a stroke or traumatic head injury.
Types of Speech Sound Disorders
There are two main types of speech sound disorders: articulation disorders and phonological disorders.
Articulation disorders involve problems making sounds. Sounds may be substituted, omitted, added, or distorted. This results in speech that is difficult for others to understand. Common problems include substituting the letter “r” with “w” (“wabbit” for “rabbit”), shortening words, or speaking with a lisp.
Phonological disorders involve patterns of sound errors. Mistakes are made with entire groups of words; for instance, sounds made in the back of the mouth may be substituted with sounds made in the front of the mouth, e.g. substituting the letter “d” for “g” (“got” for “dot”). People with phonological disorders are often able to hear these errors when others speak, without picking up on their own mistakes.
Causes & Treatment
Many times, the cause of speech sound disorders is unknown. Children may not learn how to correctly pronounce certain sounds, and this can carry over into adulthood. Other times, the cause is physical in nature. Developmental disorders, genetic syndromes, neurological disorders, hearing loss, and other illnesses may all contribute to speech sound disorders.
A speech-language pathologist (SLP) will thoroughly evaluate a patient to determine the cause of the disorder, and recommend a course of treatment. He or she will work closely with the individual to improve articulation, reduce errors, and demonstrate which sounds are correct and how to recognize when they are incorrect. This may involve teaching the rules of speech.