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The Speech Therapy Blog

What Causes Speech Problems in Adults?

Last updated Jan. 22, 2018

Speech problems in adults include any underlying condition or symptoms that can cause an adult to have difficulty with vocal communication.

They are very disturbing problems that may manifest in such forms as slurred speech, slower rate of speaking, unusually hoarse vocal sounds, stuttering, rapid speech that is hard to comprehend, as well as any other form of impairment that makes it hard for an adult to effectively express themselves to another person in a mutual language through vocal communication.

The different forms of speech problems are caused by different factors, and the severity of the problem may depend on the underlying cause.

How common are speech problems in an adult?


Speech problems are not common in adults, but when they set in, the experience is usually devastating with consequences that find expression at home, as well as at the workplace.

Major kinds of speech problems:

There are different kinds of speech problems, and it is important to mention and discuss some of the major ones before looking at the major causes of speech impediments in adults.

1. Apraxia of Speech

Apraxia of speech in adults is a serious motor speech disorder that results when messages from the brain are disrupted, and the sufferer is unable to move his or her lips or tongue to the right place to make the right sounds.

This disorder manifests even when the facial muscles are strong and functional.

2. Aphasia

This is more of a communication problem as it includes both inability to speak, read, write, or understand a language that is known before due to disturbances in the area of the brain used for language processing.

3. Dysarthria

This is a speech disorder that results from impairments of the muscles associated with vocal communication including the lips, tongue, vocal cord, and even the diaphragm.

Sufferers are unable to speak properly due to inability to control some muscles.

4. Spasmodic Dysphonia

This is a speech disorder in which the muscles that generate vocal sounds go into periods of spasm, resulting in impaired speech. It is also known as laryngeal dystonia.

5. Dysprosody

This is a speech disorder that results from compromise or elimination of one or more of the prosodic functions such as melody, intonation, pauses, stresses, accents, intensity, and vocal quality.

Though sufferers of the condition are able to comprehend language and vocalize what they want to say, they are most often unable to control the way in which words come out of their mouth.

Dysprosody is one of the rarest neurological speech disorders.

Some other types of speech problems affect adults, be that as it may, we’ll be looking at the various symptoms peculiar to most of these problems.

Signs and symptoms of speech problems in adults:

Signs of speech problems are generally obvious in adults. Once the problems sets in, both the sufferer and the people around him/her will notice the signs.

In most cases, the individual will have a perfect understanding of what he or she wants to say but will end up saying something different and try again to get the right words out.

Some cases of speech problems develop quickly while some others creep in slowly with few signs and symptoms at the initial stage. Some general signs include:

  • Difficulty in imitating or repeating speech sounds
  • Errors in form of sound distortion, wrong pronunciation, omission of words, and substitution of words
  • Abnormal reduction in speech rate
  • Impaired rhythm and intonation of speech
  • Unnecessary repetition of words in a statement
  • Sudden inability to produce any sound at all in severe cases.

Causes of Speech Problems in Adults


Speech problems in adults can be caused by a number of factors. While some are defects from birth that linger throughout life, some others are conditions that develop as a result of an accident, injury, or some other medical reasons.

We shall discuss some of the most popular causes of speech problems below.

1. Stroke

Stroke is one of the major causes of speech problems in adults. Stroke is a medical condition that results when the blood supply to the brain is disrupted, resulting in the death of brain cells due to oxygen deprivation.

Though there are reported cases of stroke in younger patients, it is more common in old people and is majorly caused by weakened blood vessels and abnormal blood pressure.

Strokes are classified based on the root cause of the condition into hemorrhagic stroke (a brain aneurysm burst or a weakened blood vessel leak) and ischemic stroke (blockage of the blood vessel due to blood clotting).

Both types of stroke can cause speech problems depending on the part of the brain that is damaged. When the part of the brain responsible for speech is affected by stroke, speech problems are inevitable.

2. Traumatic brain injury

TBI is another major cause of speech problems in adults. This form is the brain of brain injury is caused by sudden damage to the brain due to open or closed brain injury.

Open head injuries occur when an object, a bullet, for instance, penetrates the head and inflicts injury on the brain. Closed head injuries result from severe blows to the head that cause internal damage without visible damage to the head.

Traumatic brain injuries result in two kinds of brain damage. A primary brain damage occurs at the time of impact, while a secondary brain damage evolves over time after a traumatic incident. Both brain damages resulting from TBIs can cause speech problems depending on the part of the brain affected and the severity.

3. Dementia

Dementia is a broad category of brain problem that is associated with long-term memory loss and inability to think properly. The condition is peculiar to aged people and is usually irreversible.

 Though dementia is associated with speech problems, there are several other problems associated with the condition that will ultimately make the patient depend on other people for everyday activities.

4. Brain tumours

Brain tumours are also one of the major causes of speech problems in adults. Both cancerous and non-cancerous tumours in the brain can contribute to speech impairment, depending on the area of the brain affected.

The frontal lobe, for instance, is involved in language production, while the temporal lobe is involved in understanding language.

If the parts of the brain involved in either cognitive communication or the part that controls the muscles that are involved in speech production are affected, speech problems will definitely arise.

5. Progressive neurological disorders

A neurological disorder is a condition that affects any part of the central nervous system or the peripheral nervous system. Progressive neurological disorders are serious health conditions associated with progressive deterioration in functioning.

They include such notorious conditions as multiple sclerosis, Parkinson’s disease, and motor neuron disease. Most of these conditions progress gradually while some of them are more aggressive.

Though they can be managed, most progressive neurological disorders are likely to affect an individual for the rest of his or her life.

There are some pronounced characteristics of these disorders that result in speech problems. They include:

  • Cognitive impairment
  • Dysphonia (voice problems), and
  • The inability of the muscles for speaking is

Speech problems associated with progressive neurological disorders are similar to those that result from brain damages and injuries.

How to Diagnose Speech Problems in Adults


Though the signs and symptoms of speech problems are easily noticeable, it is still left for speech-language pathologists (SLP) or speech therapists to diagnose most of the discussed speech problems.

They use a combination of formal and informal assessment tools to diagnose any of the conditions and to determine its severity. They examine the patient’s oral motor abilities, the melody of speech, and speech sound production.

Speech difficulties in adults are caused by a number of reasons and the major ones have been discussed above. The list of causes is actually broad and each of them can be handled differently.

The conditions will have to be diagnosed by an expert and a speech therapist can help to manage the condition.