Speech sound disorders are speech disorders in which some speech sounds in a child’s (or, sometimes, an adult’s) native language are either not produced, not produced correctly, or are not used correctly.
Errors produced by individuals with speech sound disorders are typically classified into four categories:
Omissions: Certain sounds are not produced — entire syllables or classes of sounds may be deleted; e.g., fi’ for fish or ‘at for cat. Additions (or Commissions): an extra sound or sounds are added to the intended word.
Distortions: Sounds are changed slightly so that the intended sound may be recognized but sound “wrong,” or may not sound like any sound in the language. The best known example of a distortion is the lisp.
Substitutions: One or more sounds are substituted for another; e.g., wabbit for rabbit or tow for cow.
Most speech sound disorders occur without a known cause. A child may not learn how to produce sounds correctly or may not learn the rules of speech sounds on his or her own. These children may have a problem with speech development, which does not always mean that they will simply outgrow it by themselves. Many children do develop speech sounds over time but those who do not often need the services of a Speech-Language Pathologist to learn correct speech sounds.
Some speech sound errors can result from physical problems, such as:
- Developmental disorders (e.g. – autism)
- Genetic syndromes (e.g. – down syndrome)
- Hearing loss
- Cleft palate or other physical anomalies of the mouth
- Neurological disorders (e.g. – cerebral palsy)