Misarticulation refers to the difficulty or inability to produce speech sounds accurately. Proper speech requires precise coordination of the tongue, lips, jaw, and soft palate, each playing a key role in shaping sounds correctly. When misarticulation occurs, these sounds may be altered in various ways, including substitutions (replacing one sound with another), omissions (leaving out sounds), distortions (producing sounds imprecisely) or additions (inserting extra sounds). In adults, misarticulation most commonly presents as sound distortions, though additions, substitutions, and deletions may also be observed. Individuals with this condition are typically aware of their speech differences and may consciously attempt to correct them. Misarticulation can impact communication clarity, social interactions, and self-confidence, making recognition and appropriate intervention essential for improving speech effectiveness in everyday life.
The cause can be divided broadly into structural, neurological and functional. It has been observed that the cause can also be a combination of any 2 or all 3 factors.
- Structural causes
The cause is termed structural if a part of the body that aids in speech is having some sort of impairment or structural defects. The different structural causes are:
- Cleft lip and/or palate
A cleft in lip and/or palate might lead to misarticulation of sounds produced due to improper tongue placement, inadequate movement of the soft palate, inadequate lip closure or due to a cleft, fistula or hole which leads to hypernasality and nasal emissions.
- Macroglossia or large tongue
If the size of the tongue is much larger than the average tongue size, it could cause unclear enunciation as the tongue won’t be able to move easily and maintain a proper position while producing different sounds.
- Ankyloglossia or tongue tie
It is a condition where the band or membrane that connects the bottom of the tongue and the floor of the mouth (frenulum) is thick and short, which affects the mobility of the tongue. It has been seen that the mobility of the tongue is not much affected if the frenulum is slightly shorter or thicker than average. Speech becomes unclear if the frenulum is much thicker and much shorter than the average thickness or length.
- Tongue splitting or bifurcation
Split tongue or bifid tongue means that the tongue is spit into 2 from the tip to the centre of the tongue. It can be seen in certain types of conditions or syndromes like Goldenhar syndrome, Klippel-Feil syndrome and orofaciodigital syndrome. The split tongue is seen from birth in these conditions and can persist till adulthood if left untreated.
It is also seen that some people undergo tongue splitting as a form of body modification for cosmetic purposes. The tongue is intentionally cut from the centre till the tongue tip.
Split tongue could lead to unclear enunciation and distortions in speech.
- Microglossia or underdeveloped tongue
It is a condition where the tongue does not grow to the adult size and is shorter and narrower than the average tongue size. It can also lead to distortions in speech.
- Hearing impairment
Certain sounds like the /s/ and /sh/ sounds are difficult to be heard and a person might have sound substitutions or distortions as they are not able to get auditory feedback by listening to their and others’ speech. Misarticulation is associated with hearing impairment only if the person has impaired hearing since birth or before they learn to speak and not in the later years.
- Missing tooth/teeth
Missing tooth may or may not cause a distortion in speech. Some studies have shown that missing front tooth causes lisp and other studies have shown that enunciation is not affected due to missing tooth. However, distortion of speech sounds can happen if many teeth are missing.
- Malalignment of jaw
Having an overbite, underbite or a tilted jaw can cause misarticulation in speech that mainly consists of distortions.
- Neurological Causes
Neurological causes of misarticulation occur when there is damage to the brain, cranial nerves, or muscles involved in speech production. These structures include the tongue, lips, jaw, and soft palate—all of which work together to produce accurate speech sounds. When the nerves that control these muscles are damaged, or when the brain’s ability to send clear motor signals is impaired, speech clarity is affected. Two common neurological conditions that cause misarticulation in adults are dysarthria and apraxia of speech.
• Dysarthria
Dysarthria is a motor speech disorder that occurs due to weakness, paralysis, or incoordination of the speech muscles. It often follows a neurological event such as a stroke, traumatic brain injury, Parkinson’s disease, multiple sclerosis, or cerebral palsy. Because of nerve damage, the tone and strength of the muscles controlling the lips, tongue, soft palate, and jaw become abnormal. As a result, speech may sound slurred, slow, strained, or muffled. Individuals with dysarthria may find it difficult to control their breathing while speaking or may have trouble maintaining steady pitch and volume. This condition doesn’t affect language comprehension or intelligence, but it can make verbal communication extremely challenging and frustrating.
• Apraxia of Speech
Apraxia of speech is another neurological cause, but unlike dysarthria, the issue here is not muscle weakness. It is a disruption in the brain’s ability to plan and coordinate movements for speech. It is commonly caused by stroke, head injury, or progressive neurological diseases that affect the motor planning areas of the brain. People with apraxia often know exactly what they want to say but struggle to form the words correctly. Common articulation errors include sound substitutions, omissions, and additions. Speech may sound inconsistent. It is sometimes clear, sometimes distorted, depending on fatigue or emotional state. Unlike dysarthria, the problem in apraxia lies in the programming of speech, not the execution.
3. Functional Causes
Functional causes refer to cases where misarticulation occurs without any structural or neurological abnormalities. In adults, this often results from faulty learning patterns, for example, speech habits formed in childhood that were never corrected. A person may continue to pronounce certain sounds incorrectly because they learned them that way early on and never received targeted speech therapy.
Functional misarticulation can also develop due to psychological stress, tension, or anxiety, which can affect speech coordination.
Symptoms of Misarticulation
The main symptoms of misarticulation in adults fall under four broad categories: substitutions, omissions, distortions and additions.
- Sound Substitutions
Individuals may replace one sound with another that feels easier to pronounce. For example, using /w/ instead of /r/, as in saying “wabbit” for “rabbit.” This can result from residual childhood errors or weakened motor control affecting articulation precision.
- Sound Omissions or Deletions
It means leaving out certain sounds, especially in longer or more complex words. For instance, saying “tevision” instead of “television.” Omissions can make speech sound rushed or incomplete, often affecting intelligibility and confidence during professional or social interactions.
- Sound Distortions
Distortions happen when the correct sound is produced incorrectly or sounds unnatural. For example, a distorted /s/ that may sound slushy, whistled, or muffled. This can result from missing multiple teeth, moderate to severe dental malalignment, muscle weakness, or neurological conditions like mild dysarthria.
- Sound Additions
Sound additions occur when extra sounds are unintentionally inserted, such as saying “culay” instead of “clay.” This may happen due to overcompensation while trying to speak clearly, fatigue, or mild coordination issues involving the lips and tongue.
Treatment of misarticulation
The different treatment approaches are:
- Surgery
Sometimes surgery is required for certain conditions like split tongue, large tongue, cleft lip and/ or palate, tongue tie etc.
- Prosthesis
A prosthesis is a device that can be helpful to restore, replace or assist in having a normal or near normal function of a structure. Dental implants, artificial teeth, palatal lifts, palatal obturators are examples of prosthesis which can improve speech enunciation.
- Speech therapy
Speech therapy is important in order to have a clear enunciation. Even after surgery and prosthesis, a person might still have unclear speech as they are used to incorrect enunciation since childhood and are not able adapt to the new changes for enunciating different sounds. Also, minor adjustments may have to be made that are different from the actual mouth position due to the type of modification done. Speech therapy will also be helpful if the speech error is due to faulty learning and also if it is possible to correct speech without the need for surgery or prosthesis if the impairment is mild.
Conclusion
Clear articulation is important for a good communication. Misarticulation in adults can happen due to different types of issues. The nature and type of misarticulation can also be different depending on the underlying cause. It is important to seek therapy from a trained speech language pathologist, who will be able to assess, provide guidance for other types of treatment, if required, and correct speech errors.
