Parkinson’s disease is often linked with tremor, stiffness and changes in walking.
But Parkinson’s can also affect speech and voice.
In some people, these changes may happen early. They may even appear before more obvious movement problems are noticed.
Researchers are now paying much more attention to Parkinson’s disease voice changes. They are studying whether changes in speech and voice may help doctors identify Parkinson’s earlier.
These changes can be easy to miss. A person may think their voice sounds normal even when family members notice that it has become softer, flatter or harder to understand.
Here are five voice and speech changes that may occur with Parkinson’s disease.
1. A Softer Voice
One of the most common voice changes in Parkinson’s disease is a softer voice.
This is sometimes called hypophonia.
A person may begin speaking more quietly without realizing it.
Family members may start saying:
“Can you speak louder?”
“I cannot hear you.”
“Can you say that again?”
The person speaking may feel like they are using a normal voice.
This difference between how loud a person thinks they are speaking and how loud they actually sound is common in Parkinson’s disease.
A softer voice may be one of the first communication changes noticed by family members.
2. Less Expression in the Voice
Normal speech has many changes in pitch.
Our pitch goes up and down when we ask questions, show excitement or stress an important word.
People with Parkinson’s may start using less pitch variation.
Their speech may sound flatter or more monotone.
This does not mean they are less interested or less emotional.
The muscles and movements needed to change pitch may simply become harder to control.
Research has found that reduced pitch variation may happen even in the earlier stages of Parkinson’s disease.
3. Changes in Voice Quality
The voice itself may also begin to sound different.
It may sound:
Breathy
Rough
Weak
Hoarse
Less steady
These changes can happen because Parkinson’s affects the muscles used for breathing and voice production.
Researchers can now measure very small changes in voice quality and stability.
Some of these changes may be too subtle for a family member to notice at first.
4. Words May Become Less Clear
Parkinson’s can affect more than the voice.
It may also affect how clearly a person moves the lips, tongue and jaw during speech.
Words may begin to sound less crisp.
Consonants may not sound as clear.
Speech may become harder to understand when the person is tired or speaking quickly.
Long conversations may also be more difficult.
Family members may notice that they need to ask for repetition more often.
5. Changes in Speech Rate and Rhythm
Parkinson’s may also change how fast or slowly a person speaks.
Some people begin speaking very quickly.
Others may speak more slowly.
A person may also start a sentence at a normal speed and then become faster as the sentence continues.
Words may run together.
Pauses may occur in unusual places.
These changes can make speech harder to follow.
Why Voice Changes Matter
For many years, speech problems were often thought of as a later symptom of Parkinson’s disease.
New research suggests that this may not always be true.
Voice and speech changes may begin much earlier.
This has led researchers to study voice as a possible tool for earlier detection.
A major review published in NPJ Parkinson’s Disease in 2025 looked at speech and language changes across different stages of Parkinson’s disease.
The researchers found that voice and speech may provide useful information about early changes and disease progression.
Researchers Are Studying Voice With Smartphones
One exciting area of research involves digital technology.
Researchers are studying whether phones and other devices can detect small changes in voice and movement.
A 2025 study looked at three areas:
Voice
Finger tapping
Walking
Researchers compared people without Parkinson’s disease with people who had early and more advanced Parkinson’s disease.
They found differences in all three areas.
People with Parkinson’s had more pauses when speaking.
They also had less variation in pitch.
Walking and finger movements changed as well.
These findings suggest that doctors may one day use several types of information together to help identify Parkinson’s earlier.
Voice and Walking May Change Together
Speech and walking may seem very different.
But both require the brain to control movement.
Researchers have found links between speech changes and walking changes in Parkinson’s disease.
This may mean that speech and walking are affected by some of the same changes in the brain.
Scientists are continuing to study these connections.
Can Voice Changes Diagnose Parkinson’s Disease?
No.
A voice change alone does not mean that someone has Parkinson’s disease.
Many other things can affect the voice.
These include aging, hearing loss, reflux, vocal fold problems, medication effects and other medical conditions.
Voice analysis is still being studied as a possible screening tool.
It is not a replacement for an evaluation by a neurologist.
However, changes in voice and speech may provide another clue when they occur along with other symptoms.
Why Early Recognition Is Important
Speech changes often happen slowly.
Because of this, people may adjust without realizing it.
They may begin speaking less in groups.
They may avoid noisy restaurants.
They may stop making phone calls.
They may let a spouse speak for them.
These small changes can slowly affect confidence, independence and social connection.
Recognizing speech and voice changes earlier gives people more options.
A speech language pathologist can measure voice and speech skills and create a baseline.
Treatment can also begin before communication problems become more severe.
Speech Therapy Can Help
Speech therapy is an important part of Parkinson’s care.
One of the best studied treatments is LSVT LOUD.
LSVT LOUD is designed to help people with Parkinson’s use a stronger and clearer voice.
A large study published in The BMJ in 2024 compared LSVT LOUD with standard speech therapy and no speech therapy.
People who completed LSVT LOUD reported greater improvement in their voice related quality of life.
Research also supports speech therapy delivered through telehealth.
A randomized study published in EClinicalMedicine in 2024 found that remotely delivered speech therapy can be effective for people with Parkinson’s disease.
Telehealth may be especially helpful for people who have trouble traveling or who do not live near a clinician with Parkinson’s experience.
When Should You Consider a Speech and Voice Evaluation?
A speech and voice evaluation may be helpful if you or a family member notice changes such as:
- A softer voice
- Frequent requests to repeat yourself
- A flatter or more monotone voice
- Speech that sounds less clear
- Faster or less controlled speech
- Difficulty being heard in groups
- Voice fatigue during longer conversations
- A change in voice that continues over time
A speech language pathologist can look at vocal loudness, clarity, speech rate and overall communication.
What Researchers Are Studying Next
Research on Parkinson’s disease voice changes is growing quickly.
Scientists are studying whether voice recordings can help identify Parkinson’s earlier.
They are also studying whether voice can help track changes over time.
In the future, doctors may combine voice information with walking, hand movement and other signs.
For now, the main message is simple.
Do not ignore a lasting change in speech or voice.
A softer voice, flatter speech or reduced clarity does not automatically mean Parkinson’s disease.
But when these changes continue, especially along with other symptoms, they are worth discussing with a healthcare professional.
About the Author
The author is a medical speech language pathologist with more than 20 years of experience working with adults with communication and swallowing disorders. Clinical areas include Parkinson’s disease, voice disorders, dysarthria, aphasia, cognitive communication disorders and swallowing difficulties. She is certified in LSVT LOUD and SPEAK OUT! and provides specialized adult speech and voice therapy through Vital Voice and Speech, including teletherapy services in Florida, North Carolina and Virginia.
References
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