A lisp is a functional speech disorder that involves the inability to
correctly pronounce one or more sibilant consonant sounds, usually
Lisping is a speech disorder characterized by the inability to correctly
pronounce the sounds of
, known as the sibilant consonants. Usually
sounds are substituted for the sibilants. The word "lisp,"
for example, would be pronounced "lithp" by someone with
this speech disorder.
Many children lisp at certain stages of speech development, especially
when they lose their front primary teeth. Lisping is, therefore, sometimes
called a developmental phonetic disorder. Frontal or interdental lisp is
produced when the tongue protrudes through the front teeth when teeth are
missing and is the most familiar type of lisp. Sibilant production may be
interfered with in a number of other ways as well. These are all
classified as lisping and include excessive pressure by the tongue against
the teeth, the tongue held too far back along the midline of the palate,
and a "substitute hiss" produced in the throat or larynx.
Sometimes children with functional
have problems making other sounds, such as
. When a child cannot produce these sounds correctly, the condition is
usually not considered a true lisp, but is a functional speech disorder.
Children can have a functional speech disorder as well as a developmental
phonological disorder. The latter is not a matter of being able to
physically make a specific sound but is a language disorder. These
children have trouble organizing the sounds of speech in common patterns
and may consistently replace one sound with another. For example, a child
may say "wun" instead of "sun" or
"doe" instead of "so."
There are four main types of lisps.
According to the National Institute on Deafness and Other Communication
Disorders, about one in six people in the United States (42 million adults
and children) has a communication disorder. Of them, 14 million have a
speech, voice, or language disorder that is not linked to hearing loss.
Functional speech disorders with no known cause, such as lisping, affect
10 percent of the population; 8–9 percent serious enough to require
treatment. Nearly 5 percent of first graders have functional speech
disorders, and 50–70 percent of all children with functional speech
disorders struggle academically throughout elementary school and high
Causes and symptoms
As a functional speech disorder, lisping has no clear known cause. It is
often referred to as a speech delay of unknown origin. Structural
irregularities of the tongue, palate, or teeth (including abnormalities in
the number or position of the teeth) may be implicated in lisping, but
they generally are not the main causes. Mild hearing loss involving high
frequencies may also impair a child's ability to hear language
correctly and be able to repeat phonetic sounds. In some cases, a child
with no physical abnormality will develop a lisp. It has been thought that
some of these children may be imitating another child or an adult who
Lisping is also associated with immature development. Some children will
adopt a lisp as a means of gaining attention. Other children will begin to
lisp after they have experienced unusual stress or trauma. This behavior
is part of a regression into a more secure period and can include other
types of regressive behaviors such as bed wetting or wanting to
with the light on in the bedroom.
One theory of the cause of lisping is the result of tongue thrusting, a
physiological behavior that causes the tongue to flatten and thrust
forward during swallowing and speaking. It is suggested that
, overuse of pacifiers, bottle feeding, and recurrent upper respiratory
illnesses cause tongue thrusting. Thumbs (or fingers), artificial nipples,
and pacifiers keep the tongue flat and do not allow the muscles of the
tongue to develop in a normal fashion. When the child speaks, the tongue
shoots forward, creating a lisp.
Frequent upper respiratory illnesses often stuff the nose, forcing these
children to breathe through their mouths. The sounds that they make when
they speak may be thick and garbled, and may encourage lisping. Closing
the mouth and teeth to make
sounds cuts off the breath, so children compensate by trying to speak
without closing their mouths completely. Thus, a lisp develops.
The interdental lisp and the dentalized lisp are common in normal speech
development. However, if they persist well past four-and-one-half years
and garble the speech so that the child is not understood, he or she
should be evaluated. The evaluation will determine if there is a
physiological basis for the lisp and identify the type of lisp. In some
cases, the child will be evaluated and observed for several months or
longer to see if the condition can be outgrown. Lateral and palatal lisps
are not found in typical speech development and should be evaluated by a
speech-language pathologist. If untreated, lisping can persist into
For some children, everything they say seems to be interdental. In these
cases, there may be an obstruction of the nose because of infection,
allergy, enlarged adenoids, or other facial problems. Excessive
interdental speech can also be related to mouth breathing and sucking
habits. These children should be seen by a physician to treat the health
problems and then referred to a speech-language pathologist to correct the
A physician can determine whether there are structural irregularities
within the mouth or problems with the child's hearing, and can
and nasal problems. However, true assessment of a child's ability
to make speech sounds must be done by a speech-language pathologist. The
child's medical history will be taken and the speech-language
pathologist will examine the anatomy of the child's mouth and the
movements it can make. Next, the child's speech and reading aloud
is often recorded for later analysis. This speech sample will also yield
information about the quality of the child's voice, how fluent
speech occurs, and the child's semantic and physical sound-making
Typical treatment is called articulation therapy. The speech-language
pathologist finds out whether the child can hear proper speech sounds, and
proceeds to read a list of words with specific sounds that the child is
having trouble articulating. Lists of contrast words are also read so that
the child can hear the subtle differences in word sounds. Therapy then
moves to working on the position in the word where the sound occurs; that
is, at the beginning, in the middle, or at the end. Specific word
exercises follow, beginning with single sounds, then syllables, and moving
on to words, phrases, and sentences. Finally, the child participates in
controlled conversations such as talking casually during a meal.
Most lisps are developmental and resolve themselves in children by the
time they are about five to eight years old. If they last longer or are of
a specific type, speech therapy is recommended. The outcome of speech
therapy is usually quite good. Depending on the specifics of the therapy
and the nature of the lisp, treatment can be relatively short term,
lasting only a few months. Some cases may take a year or more.
Parents can reduce the risk of a lisp developing because of tongue
thrusting by restricting
or choosing to breastfeed their babies. They can also speak clearly in
complete sentences around their children and not use baby talk. They
should treat allergies and respiratory illnesses immediately to keep the
nose open and breathing free. The child's hearing and teeth should
be checked periodically to make sure he or she can hear speech clearly and
form words correctly. Parents can also encourage the musculature of the
mouth by showing children how to drink from straws and how to blow
bubbles. In addition, playing word and naming games encourages good speech
development and stimulates learning.
—The roof of the mouth.
—A physiological behavior that causes the tongue to flatten and
thrust forward during swallowing and speaking.
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American Speech-Language-Hearing Association
10801 Rockville Pike Rockville, MD 20785. (301) 897-5700. Web site:
Council for Exceptional Children.
Division for Children with Communication Disorders. 1920 Association
Drive Reston, VA 22091. (703) 620-3660.
National Institute on Deafness and Other Communication
National Institutes of Health. 31 Center Drive, MSC 2320 Bethesda, MD