Slurred speech that comes on suddenly must be treated as a stroke until a doctor says otherwise. Call 112 or 999 in Ireland, 999 in the UK or 911 in the US straight away. Do this even if the speech returns to normal while you wait.
Slurring has other causes too. Drinking too much alcohol is the most familiar. Some medicines can affect speech. Conditions that affect the nerves and muscles can cause slurring that comes on gradually. Examples include myasthenia gravis, multiple sclerosis (MS), Parkinson's disease and motor neurone disease (MND).
Speech that has slowly become unclear over weeks or months still needs a GP appointment. This page is about slurred speech, where words come out unclear. If your speech is clear but you struggle to find the right word, see our guide to word-finding difficulty.
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Call 112 or 999 in Ireland, 999 in the UK or 911 in the US if someone suddenly has:
Call even if the symptoms go away. Note the time they started. Do not drive the person to hospital yourself.
Also call 112, 999 or 911 if slurred speech comes with:
Contact your GP urgently, or an out-of-hours GP, if:
See a GP if:
FAST is how health services teach people to spot a stroke. The HSE, Ireland's health service, describes the signs like this:
The NHS uses the same word. It says speech problems in a stroke can mean you "slur your words or sound confused". FAST stands for face, arms, speech and time to call 999. In the US, MedlinePlus suggests asking the person to repeat a simple sentence, then calling 911.
The HSE says the FAST signs identify most strokes, but not all. Other stroke symptoms include sudden blurring or loss of vision, dizziness, confusion, problems with balance and difficulty swallowing. Our article on the FAST signs and stroke risk explains why speed matters.
A mini-stroke, or transient ischaemic attack (TIA), causes the same symptoms but they pass. The NHS says the effects last a few minutes to a few hours and fully go within 24 hours. In the early stages, the NHS says it is not possible to tell a TIA from a full stroke.
So the advice is the same: call an ambulance. Both the HSE and NHS say you should see a specialist within 24 hours. Think you had a TIA in the past and never got help? The HSE advises contacting your GP, local hospital or out-of-hours service as soon as possible.
Doctors separate two kinds of speech problem:
You can have both at once, and a stroke can cause either. MedlinePlus notes that people with dysarthria may also have problems swallowing.
This is the cause that matters most, because treatment is time-critical. The NHS lists stroke among the common causes of dysarthria. Slurred speech from a stroke usually starts suddenly, often with weakness of the face or arm.
MedlinePlus lists alcohol intoxication as a cause of dysarthria. The NHS lists slurring words or being unable to speak among the symptoms of alcohol poisoning. Other signs include confusion, being unable to stand, being sick, slow breathing and seizures.
The NHS says to call 999 if you think someone has alcohol poisoning, and to stay with them. Sit them up if awake, or use the recovery position if they have passed out.
Drinking does not rule out a stroke or a head injury. If you are not sure why someone's speech is slurred, get help.
The NHS advises calling 999 if someone has hit their head and has problems with understanding or speaking. The same applies to new numbness or weakness, a seizure, or not being able to stay awake. If you have had a head injury, see our guide to concussion.
The NHS says a confused person may not be able to think or speak clearly or quickly. It advises A&E or 999 if someone suddenly becomes confused. Common causes include infections, stroke, low blood sugar in people with diabetes, some medicines, and alcohol or drugs.
The NHS lists difficulty speaking among migraine aura symptoms. Aura should not last longer than 1 hour. The NHS advises calling 999 if a headache comes with problems speaking. A first episode, or one unlike your usual aura, should be treated as a possible stroke.
The NHS says dysarthria can be a side effect of some medicines, such as some epilepsy medicines. It lists changes to coordination, balance and speech among common side effects of carbamazepine. MedlinePlus also lists strong painkillers (narcotics) and phenytoin.
If you take lithium, the NHS lists difficulty speaking among the signs of lithium toxicity. It treats this as an emergency. Never stop or change a prescribed medicine yourself without advice, except where your medicine's own emergency advice tells you to.
The NHS describes myasthenia gravis as a rare long-term condition that causes muscle weakness. It often affects the muscles for the eyes, face, chewing, swallowing and speaking. Slurred speech, droopy eyelids and double vision are common symptoms.
A key feature is that symptoms get worse when you are tired. The NHS says many people are worse towards the end of the day and better after sleep. Our guide to double vision covers the eye symptoms.
The NHS says MND causes muscle weakness that gets worse over months or years. It usually affects people over 50. In one type, progressive bulbar palsy, the early symptoms are slurred speech and problems swallowing.
Early MND symptoms can look like other, less serious conditions. The NHS says muscle twitches are common and very rarely serious; see our guide to muscle twitching.
The NHS lists Parkinson's disease and MS among the common causes of dysarthria. In Parkinson's, the main symptoms are tremor, slow movement and stiffness, which usually develop gradually. MS symptoms vary widely and may come and go. See essential tremor or Parkinson's for more on Parkinson's.
NHS inform, Scotland's health information service, lists slurred speech, a new stutter and hoarse speech among functional speech symptoms. FND is a problem with how the nervous system works, not damage to it. A specialist diagnoses it from features found on examination. Read our guide to functional neurological disorder.
MedlinePlus lists other causes of dysarthria. These include facial weakness such as Bell's palsy, facial injury, head and neck cancer surgery, and poorly fitting dentures. The NHS lists brain tumours, which can cause speech problems that develop slowly. Some lifelong conditions, such as cerebral palsy, also affect speech.
This is not a way to diagnose yourself. It shows the details doctors find useful.
MedlinePlus says your doctor will take a history and examine you. A family member may need to help with the history. Expect questions such as:
Tests depend on what the doctor finds. MedlinePlus lists blood tests, a CT or MRI scan of the head, and an EMG test of muscles and nerves. Other options include an EEG, a lumbar puncture and a swallowing study. The NHS says people with dysarthria are usually referred to a speech and language therapist.
MedlinePlus suggests giving the person plenty of time, and encouraging them to speak slowly and use gestures. Pen and paper, or typing on a phone, can help. Speak in a normal tone and keep the room calm.
A speech and language therapist can teach exercises and strategies, or suggest communication aids.
The NHS says stress or tiredness may make dysarthria worse in people who already have it. In myasthenia gravis, symptoms often get worse as the day goes on. Do not put new, sudden slurring down to tiredness. Call for help.
Treat it as an emergency. This can be a TIA, and the NHS says you cannot tell a TIA from a stroke early on. Call 112, 999 or 911. If it happened in the past and you never got checked, contact your GP urgently.
We could not find an NHS or HSE source that lists anxiety as a cause of slurred speech. Do not assume anxiety is the reason. Get sudden slurring checked as an emergency, and gradual changes checked by your GP.
This article is general information, not medical advice. It cannot diagnose the cause of your symptoms. If speech becomes slurred suddenly, call 112 or 999 (Ireland), 999 (UK) or 911 (US). Talk to your GP or pharmacist before starting, stopping or changing any medicine.
Reviewed by: Proco Team
Last updated: November 2026