Table 8. Developmental speech disorders.

Disorder	Description
Speech sound disorder	Also described as functional articulation disorder or phonological disorder. Characterized by errors in articulation and speech sounds, consistent substitution of simple sounds for complex sounds or single consonants for blended consonants, dropped consonants, and errors within words. Problem may not be recognized until preschool
Stuttering	Disturbed speech fluency with atypical rate and rhythm, and repetitions of sounds, syllables, words, and phrases generally accompanied by evidence of stress or physical tension. There may be sound prolongations, interjections, pauses within words, blocking of words. Typical onset between 2 and 7 years with peak at age 5 years
Resonance disorders	Can be either hypernasal or hyponasal voice due to anatomical factors. Hypernasality may be due to dysfunction of the velopharyngeal mechanism, seen for example in cleft palate. Hyponasality is seen, for example, in nasal congestion, upper respiratory infections, nasal anomalies, hypertrophied adenoids
Dysarthria	Due to dysfunction of the neuromuscular or motor mechanism for speech production (e.g., cerebral palsy). Characterized mainly by inconsistent misarticulations of speech sounds and words, poor intelligibility, and slow speech
Verbal dyspraxia and speech programming disorder	Both terms describe similar types of largely speech production problems. These disorders may significantly influence expressive language as well

Used with permission from: Patel DR. Principles of developmental diagnosis. In: Greydanus DE, Feinberg A, Patel DR, et al. editors. Pediatric Diagnostic Examination. New York: McGraw Hill Medical, 2006:629-44.