A communication disorder is an impairment in the ability to receive, send, process, and comprehend concepts or verbal, nonverbal and graphic symbol systems. A communication disorder may be evident in the processes of hearing, language, and/or speech. A communication disorder may range in severity from mild to profound.

A speech disorder is an impairment of the articulation of speech sounds, fluency and/or voice.

An articulation disorder is the atypical production of speech sounds characterized by substitutions, omissions, additions or distortions that may interfere with intelligibility.

A fluency disorder (stuttering) is an interruption in the flow of speaking characterized by atypical rate, rhythm, and repetitions in sounds, syllables, words, and phrases. This may be accompanied by excessive tension, struggle behavior, and secondary mannerisms.

A voice disorder is characterized by the abnormal production and/or absences of vocal quality, pitch, loudness, resonance, and/or duration, which is inappropriate for an individual's age and/or sex.

A language disorder is impaired comprehension and/or use of spoken, written and/or other symbol systems. The disorder may involve (1) the form of language (phonology, morphology, syntax), (2) the content of language (semantics), and/or (3) the function of language in communication (pragmatics) in any combination.

Form of Language

• Phonology is the sound system of a language and the rules that govern the sound combinations.
• Morphology is the system that governs the structure of words and the construction of word forms.
• Syntax is the system governing the order and combination of words to form sentences, and the relationships among the elements within a sentence.

Content of Language

• Semantics is the system that governs the meanings of words and sentences.

Function of Language

• Pragmatics is the system that combines the above language components in functional and socially appropriate communication.