Understand what dysarthria is, how its different types and causes can affect speech, whether it can be cured, and how speech therapy can support communication.
Written by: William Huynh, MPSA-CPSP, Director of Brighter Futures Allied Health
Published: 22 August 2026
Disclaimer: The information on this page is for general education only and should not be used as a substitute for professional assessment or personalised clinical advice. If you have concerns about speech, language, voice or swallowing, speak with a qualified speech pathologist or appropriate healthcare professional.
Dysarthria is a speech disorder that occurs when changes affecting the muscles or neurological systems involved in speech make it difficult to speak clearly. Speech may sound slurred, weak, slow, fast, quiet or less precise, depending on the underlying cause and type of dysarthria.
Dysarthria can affect people of any age, although it is particularly relevant in adults with neurological conditions or injuries that affect speech. How common it is varies considerably depending on the underlying condition. It can also occur in children, including in association with congenital or neurological conditions.
Clinician’s Notes: While their names may sound similar, dysarthria and dysphasia are different conditions that affect different aspects of communication. Dysarthria affects the physical production of speech, making it difficult to control the movements needed for clear speech. Dysphasia affects language, which can make it difficult to find words, understand language, form sentences, or express ideas through speech or writing. Both can benefit from assessment by a speech pathologist.
Dysarthria can have many different causes, ranging from neurological conditions to brain injuries and other factors that affect speech. Some causes develop gradually, while others can lead to sudden changes in speech.
Dysarthria is classified into several types based on the part of the nervous system or speech motor system that has been affected. Each type can have a different pattern of speech changes, although a person may also have features of more than one type.
Flaccid dysarthria is associated with weakness or reduced muscle tone affecting the muscles used for speech.
Presentation: Speech may sound weak, breathy or quiet, with imprecise pronunciation and difficulty maintaining a steady voice.
Spastic dysarthria is associated with increased muscle tone and reduced flexibility or control of the muscles involved in speech.
Presentation: Speech may sound slow, strained or effortful, with reduced clarity and changes in voice quality.
Ataxic dysarthria results from impaired coordination of the movements needed for speech, commonly involving the cerebellum or its connections.
Presentation: Speech may sound irregular or uncoordinated, with uneven rhythm, variable loudness and imprecise pronunciation.
Hypokinetic dysarthria is associated with reduced or smaller movements of the speech muscles and is commonly seen in Parkinson’s disease.
Presentation: Speech may become quiet, fast or monotone, with reduced variation in pitch and loudness and less precise articulation.
Hyperkinetic dysarthria involves involuntary or excessive movements that interfere with the control of speech.
Presentation: Speech may be unpredictable, with sudden changes in voice, loudness, rate or rhythm and interruptions caused by involuntary movements.
This type occurs when pathways controlling speech movements are affected on one side of the upper motor neuron system.
Presentation: Speech may sound mildly slurred or less precise, with weakness or reduced control affecting one side of the face or speech muscles.
Clinician’s Notes: In addition to the types above, mixed dysarthria occurs when a person has features of two or more types of dysarthria. This can happen when an underlying condition affects multiple areas of the nervous system involved in speech. The way it presents will depend on the combination of types, so a person may experience a mix of weak, strained, uncoordinated or involuntary speech characteristics.
Whether dysarthria can be cured depends largely on its underlying cause. When speech changes are linked to a temporary or treatable cause, they may improve as the underlying condition is addressed. For stable injuries or long-term conditions, speech therapy focuses on improving or maintaining communication rather than reversing the underlying cause.
A speech pathologist can assess how dysarthria is affecting speech and develop strategies to support clearer, more effective communication. For progressive conditions, therapy may also focus on adapting communication strategies and introducing alternative ways to communicate as speech changes over time.
If you or someone close to you is experiencing dysarthria, reputable online resources can provide useful information about the condition, its causes and available support.
Online resources can be a helpful starting point, but they cannot determine the cause of an individual’s speech difficulties. If dysarthria is affecting speech clarity or everyday communication, a speech pathologist can assess the person’s speech and recommend practical strategies and supports based on their needs and underlying condition.
William Huynh is a senior speech pathologist and the director of NDIS-registered provider Brighter Futures Allied Health. He has over a decade of experience working with children and adults with complex communication needs, including disability, dysphagia, and acquired language impairments. William has completed specialist training in approaches such as Key Word Sign, LAMP Words for Life, Grid 3, and Hanen’s More Than Words. He also supervises speech pathologists and student placements, supporting evidence-based and family-centred practice.
