nological disorder and articulation disorder . A speech sound disorder is diagnosed when
speech sound production is not what would be expected based on the child’s age and devel-
opmental stage and when the deficits are not the result of a physical, st ructural, neurological,
or hearing impairment. Among typically develo ping children at age 4 years, overall speech
should be intelligible, whereas at age 2 years, only 50% may be understandable.
Associated Features Supporting Diagnosis
Language disorder, particularly expressive de ficits, may be found to co-occur with speech
sound disorder. A positive family history of speech or language  disorders is often present. 
If the ability to rapidly coordinate the articu lators is a particular aspect of difficulty,
there may be a history of delay or incoordinati on in acquiring skills that also utilize the
articulators and related facial musculature; among others, these sk ills include chewing,
maintaining mouth closure, and blowing the no se. Other areas of motor coordination may
be impaired as in developm ental coordination disorder. Verbal dyspraxia  is a term also
used for speech prod uction problems.
Speech may be differentially impaired in ce rtain genetic conditions (e.g., Down syn-
drome, 22q deletion, FoxP2  gene mutation). If present, these should also be coded.
Development and Course
Learning to produce speech sounds clearly and accurately and learning to produce con-
nected speech fluently are developmental skills. Articulation of speech sounds follows a