An articulation disorder is a difference in the way that a student says a speech sound, which can interfere with how well a student is understood.
ASHA Speech Sound Disorders: https://www.asha.org/public/speech/disorders/Speech-Sound-Disorders/
A fluency disorder, also known as stuttering or cluttering, is an interruption in the flow of speaking characterized by atypical rate, rhythm, and repetitions in sounds, syllables, words, and phrases.
ASHA Stuttering: https://www.asha.org/public/speech/disorders/stuttering/
The Stuttering Foundation: https://www.stutteringhelp.org/
National Stuttering Association: http://www.nsastutter.org/
A voice disorder is when there is an abnormal production and/or absence of vocal quality, pitch, loudness, resonance, and/or duration, which is inappropriate for an individual's age.
A language disorder is impaired comprehension and/or use of spoken and/or written. A language disorder may involve receptive (understanding), expressive (expressing), and/or pragmatic (social) language difficulties.
ASHA Language Disorders
Written Language: https://www.asha.org/practice-portal/clinical-topics/written-language-disorders/
Pragmatic/Social Language: https://www.asha.org/practice-portal/clinical-topics/social-communication-disorder/
Augmentative/Alternative Communication (AAC) systems are used to help individuals with severe expressive and/or receptive language disorders. Augmentative/Alternative Communication may be required for individuals demonstrating impairments in gestural, spoken, and/or written modalities.