Individuals with unintelligible or inferior speech and oral communications. Can cause low self esteem, anxiety.

Defects or disturbances can arise in various parts of the nervous system, muscles, and other apparatus involved in speech, leading to an inability to communicate effectively. Some of these disorders are strictly disturbances of language rather than of speech, since they result from an impaired ability to understand or to form words in the language centers of the brain, rather than from any fault of the apparatus of speech production.

See language disorders.