What Is Dysarthria? Causes, Signs and Support

Dysarthria is a speech difficulty that happens when the muscles used for speaking become weak, slow or poorly coordinated. The person knows what they want to say, but their speech may sound slurred, slow, quiet or strained, because the lips, tongue, jaw, voice and breathing muscles cannot move as precisely as speech needs. It is a difficulty with the physical production of speech — not with language, thinking or intelligence.

Dysarthria can be mild, so that only family notice the change, or more severe, so that speech is very hard for others to understand. Either way, it can be frustrating and tiring: the words are fully formed inside, but they do not come out as clearly as the person intends.

This article explains dysarthria in plain language for adults living with it and for the families who support them. It cannot say what is causing one particular person’s speech changes — only an assessment can do that — but it can help you recognise the pattern and know where to turn.

An older man sitting on a sofa at home, chatting calmly with his wife

Key Takeaways

Dysarthria is a difficulty with the muscles of speech, not with language, thinking or intelligence.
It happens when the muscles used for speaking — lips, tongue, jaw, voice and breathing muscles — become weak, slow or poorly coordinated.
Common signs include slurred sounds, a slow or uneven pace, a quiet voice, and speech that sounds strained, breathy, nasal or flat.
Dysarthria has several possible causes, including stroke, brain injury and conditions that affect the nerves and muscles over time.
A speech and language therapist can assess the speech and work with the person and their family on strategies, therapy and, where helpful, communication aids.
Sudden speech changes are an emergency — a possible stroke. Call the local emergency number immediately.

What dysarthria is

Speaking is one of the most finely timed movements the body makes. To produce clear speech, the brain sends rapid, precise instructions to a whole team of muscles: the breathing muscles power the voice, the vocal cords shape the sound, and the lips, tongue, jaw and soft palate mould that sound into words — many movements a second, all in the right order.

Dysarthria happens when those muscles cannot carry the instructions out as well as before. They may be weaker than they should be, slower to move, stiff or tense, or poorly coordinated with one another. The result is speech that is less clear, less strong or less steady than the person intends.

What causes dysarthria?

Dysarthria is a sign that something has affected the brain, nerves or muscles that control speech. It is not a condition that people catch, and it is not caused by anything the person has done wrong. In general terms, the causes fall into a few groups:

A stroke or a brain injury, which can damage the parts of the brain that send instructions to the speech muscles, or the pathways carrying those instructions.
Conditions that develop over time and affect the nerves or muscles involved in movement and speech. In these situations dysarthria may come on gradually and change slowly.
Conditions that mainly affect the muscles themselves, where the messages arrive but the muscles cannot respond with their usual strength.

Dysarthria can begin suddenly, as after a stroke, or gradually, over months. It can stay much the same, improve, or change over time, depending on the cause. Because the cause matters for what happens next, new speech changes should always be discussed with a doctor, who can arrange the right medical checks and a referral for an assessment. General information about dysarthria is also available from the National Institute on Deafness and Other Communication Disorders (NIDCD) and ASHA.

Signs people notice

The signs of dysarthria vary from person to person, depending on which muscles are affected and how severely. Families are often the first to notice, sometimes before the person themselves has words for the change.

Slurred or imprecise speech sounds

The most recognisable sign is that the sounds of speech are no longer crisp. Consonants — the sounds that give words their shape, like p, t, k, s and sh — may come out softened or only partly formed, so words run into one another and the edges between them blur. Listeners may understand the gist but miss individual words, especially names and new information.

A slow or uneven pace

Many people with dysarthria speak more slowly than before, because each word takes more effort to form, sometimes with pauses in unexpected places while the mouth prepares the next sound. Some people show the opposite pattern — short, rushed bursts of speech that tumble out unevenly. Either way, the natural rhythm of conversation changes, and both speaker and listener may need more time.

A quiet voice

Speech is powered by breath, so when the breathing muscles are weaker, or breath and voice are not well coordinated, the voice becomes quieter. The person may fade towards the end of a sentence, need extra breaths to finish, or be hard to hear over background noise. Talking on the telephone can be especially tiring, because the listener has no facial expressions or gestures to help.

A strained, harsh or breathy voice

The voice itself may sound different. For some people it takes on a strained or tight quality, as if the words have to be pushed out, and talking for long feels like hard physical work. For others the voice is breathy and airy, with breath escaping around the words because the vocal cords are not closing as firmly as they should. Neither pattern is anything the person is doing wrong — most people are trying just as hard to be clear as they ever did.

Less melody and expression

Speech normally rises and falls: we lift our voices at the end of a question, stress the important word and vary our tone to show feeling. When the speech muscles are affected, that melody can flatten, so speech sounds more monotone. A flatter voice does not mean flatter feelings — the person may feel just as much warmth, humour or urgency as before, but the voice is less able to show it.

Changes across the day, and with emotion

A pattern families describe again and again is that speech is clearer when the person is rested and harder when they are tired, rushed or upset. Speaking with weakened muscles is genuinely hard work, and precision fades with fatigue. Strong feelings add pressure too: just when the person most wants to be understood, their speech may become less clear. Knowing this helps families plan important conversations for the person’s best times, and slow difficult moments down rather than hurrying them.

A woman sitting in a bright café, talking with a friend over coffee

How dysarthria differs from aphasia and apraxia of speech

Dysarthria is sometimes confused with two other speech and language difficulties, and separating them helps, because the support for each is different:

Dysarthria is about the muscles. The person knows the words and the sentences; the mouth, voice and breathing cannot carry them out clearly.
Aphasia is about language itself — finding words, building sentences and understanding what others say. The muscles may work perfectly; it is the words that are hard to reach.
Apraxia of speech is about planning and programming the movements of speech. The muscles are not weak, but the brain’s instructions for sequencing the movements go astray, so speech comes out inconsistently and effortfully.

The three can occur together, which is one reason a full assessment matters. Our guide to motor speech disorders explains the overall picture, and our comparison of dysarthria and apraxia of speech covers the differences in more detail.

What an assessment usually involves

A speech and language therapist assessing dysarthria will usually listen carefully to the person’s speech in conversation and in set tasks, and look at how each part of the speech mechanism is working. An assessment may cover:

How the lips, tongue, jaw and soft palate move, both on their own and in speech.
How breathing supports the voice, and how the voice sounds.
How clear the speech is to an unfamiliar listener (often called intelligibility).
How speech changes with longer sentences, background noise or tiredness.
Whether language, understanding or swallowing are affected too, because the same muscles and pathways can be involved.

The therapist will also ask what matters most to the person and their family — being understood by grandchildren, managing in a social group, keeping up at work — because those everyday goals shape what therapy focuses on.

A man sitting at a table talking with a speech and language therapist in a bright room

What therapy may involve

Therapy for dysarthria is planned by the therapist around the individual’s pattern of difficulty and their own goals. In general terms, it may involve:

Working on the speech mechanism — for example, practising steadier breath support for speech, a stronger or clearer voice, or more precise movements of the lips and tongue.
Clear-speech strategies — such as slowing down slightly, pausing between phrases, emphasising key words, and keeping sentences shorter, so listeners can follow more easily.
Communication strategies for both partners — the changes in environment, pace and checking habits described in the next section, which often make as much difference as anything practised in sessions.
Communication aids, where helpful — for times when speech is hardest, simple supports such as a letter or picture board, writing things down, or a text-based or voice-output device can sit alongside speech, not replace it.

One important note about exercises: any speech or voice exercises are chosen for the individual after assessment, and they need to be taught and supervised by a qualified speech and language therapist, who can make sure they are done safely and in a way that suits the person. This article describes therapy only as a general overview; please do not start an exercise programme based on general information alone.

How much speech changes with therapy varies a great deal, and no particular outcome can be promised. For many people, the combination of therapy, strategies and time makes everyday communication work noticeably better, even where speech does not return exactly to how it was.

Everyday communication strategies

Alongside therapy, some gentle, everyday habits help most conversations. These are general suggestions for families, not personalised advice:

Face each other, and reduce background noise. Turn off the television or radio, and sit where you can see each other’s faces — lip movements and expressions carry a great deal of meaning.
Allow plenty of time. Rushing makes speech harder. Unhurried conversation, with natural pauses, gives the muscles their best chance.
Ask for the key word. If a sentence gets lost, asking for the most important word again, said slowly, often unlocks the whole message.
Be honest about understanding. It is kinder to say “I got the first part but missed the end” than to nod along, which can leave important things missed and both of you frustrated.
Confirm as you go. Repeating back what you understood — “So you’d like to go on Thursday?” — checks the message and shows the person they are being heard.
Let the person speak for themselves. It is tempting to finish sentences or translate for them. Sometimes that help is welcome, but most people prefer to be asked first, and to keep their own voice in conversation.

A family sitting together in a living room at home, talking and listening to one another

When to seek help

One situation is an emergency, and it comes first. Sudden speech changes can be a sign of a stroke happening now. If someone’s speech suddenly becomes slurred, difficult or impossible to understand, or they suddenly lose speech — especially alongside a drooping face or weakness in an arm — call your local emergency number immediately. The same applies if someone is choking or having difficulty breathing. Do not wait to see if it passes; urgent medical help matters more than anything else.

Otherwise, it is worth seeking advice whenever speech has changed and stayed changed, or is gradually changing:

Speech that remains slurred, quiet or hard to understand after an illness or injury — raise it with the person’s doctor and ask about a referral to a speech and language therapist; in many places you can also contact a therapist directly.
Speech that is slowly becoming less clear over time, even without a single clear starting point.
Any difficulty with eating, drinking or swallowing alongside the speech changes, since the same muscles can be involved — raise this promptly with a doctor.

Support is not only for the first weeks after an event. It is reasonable to ask for an assessment at any stage if communication is difficult or changing. You can also read more about stroke and its effects at stroke.org, and general information about communication difficulties via ASHA or your own national health authority.

Questions to ask a therapist

If you arrange an assessment or a first appointment, these questions can help you get the most from it:

Which parts of the speech mechanism are affected, and what does that mean for everyday talking?
How is the person best understood at the moment — what seems to help most?
What might therapy involve, and what would sessions focus on first?
Are there strategies or things to practise at home between sessions, and how should we do them?
Would any communication aids be useful alongside speech, for the times when speech is hardest?
How will progress be reviewed, and what changes should we watch for or report?

Frequently asked questions

What is dysarthria, in simple terms?

Dysarthria is a speech difficulty caused by weakness, slowness or poor coordination of the muscles used for speaking — the lips, tongue, jaw, voice and breathing muscles. The person knows what they want to say, but their speech comes out less clearly than before: slurred, slow, quiet, strained or flat-sounding.

What are the most common signs of dysarthria?

The signs families notice most are slurred or imprecise sounds, a slower or more uneven pace, a quieter voice, a strained or breathy quality, flatter melody and expression, and sometimes a nasal sound to the speech. Speech is often clearer when the person is rested and harder when they are tired, rushed or upset.

Is dysarthria the same as aphasia?

No. They are different difficulties, although they can happen together, for example after a stroke. Aphasia affects language — finding words, forming sentences and understanding speech. Dysarthria affects the physical production of speech: the words are there, but the muscles cannot shape them clearly. An assessment can tell which are present.

Can dysarthria happen without a stroke?

Yes. A stroke is one cause, but anything that affects the parts of the brain, nerves or muscles controlling speech can cause dysarthria — a head injury, for example, or a condition that develops gradually over time. Whatever the cause, new or changing speech should be discussed with a doctor.

Will speech exercises help, and can we start them ourselves?

Therapy may include exercises for breathing, voice or the speech muscles, but they are chosen for the individual after an assessment. Exercises that suit one person may not suit another, so they should be individually assessed, taught and supervised by a qualified speech and language therapist rather than started from general information.

Will speech get better?

It varies a great deal from person to person, and no one can promise a particular outcome. Some people find their speech becomes clearer over time, especially with therapy and practice; others live with longer-term changes and find that strategies and communication aids make conversation work well. A therapist can assess the speech honestly, work on what can be improved, and help the whole family communicate as well as possible.

A gentle next step

Living with speech that does not come out as intended can be tiring and, at times, lonely — for the person speaking and for the people who love listening to them. An assessment can explain what is happening and what might help, and small changes in everyday conversation can make a real difference. If you would like to talk about dysarthria or about speech changes you have noticed, you are very welcome to get in touch online. There is no obligation and no pressure: just a friendly first conversation, at your pace.

By Hamayal Adnan, Speech-Language Pathologist

This article is for general educational purposes only and is not medical advice. It does not replace an assessment by a qualified speech and language therapist or other healthcare professional. Every person is different. If you have concerns about speech, language, feeding or swallowing, please seek professional advice. In an emergency, call your local emergency number.

What Is Dysarthria? Causes, Signs and Support Explained

Key Takeaways

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What dysarthria is

What causes dysarthria?