A language disorder is a deficit or problem with any function of language
Speech and language disorders are extremely common. They can range from
slow acquisition of language to sound substitution or
to the inability to understand or produce and language at all. The
federal Agency for Healthcare Research and Quality estimated in 2002 that
communication disorders cost the United States between $30 and $154
billion annually in lost productivity and money spent on medical care,
, and remediation.
Speech and language pathologists and neurologists (doctors who specialize
in the brain and nervous system) have known for about 100 years that
certain areas in the left hemisphere of the brain—Broca's
area in the posterior frontal lobe and Wernicke's area in the
temporal lobe—are centrally involved in language functions. Damage
to Broca's area results in problems with language fluency:
shortened sentences, impaired flow of speech, poor control of rhythm and
intonation, and a telegraphic style with missing inflections. Damage to
Wernicke's area produces speech that is fluent and often rapid, but
with relatively senseless content, many invented words, and word
With the invention of new technologies, including
(CT) scans and
magnetic resonance imaging
(MRI), several studies have looked at the
in very young children with lesions in the traditional language areas of
the brain. There is surprising agreement among the studies in their
results: all find initial delays in language development followed by
remarkably similar progress after about age two to three years. Lasting
deficits have not been noticed in these children. Surprisingly, there are
also no dramatic effects of laterality; lesions to either side of the
brain seem to produce virtually the same effects. However, most of the
data comes from conversational analysis or relatively unstructured
testing, and these children have not been followed until school age.
Nevertheless, the findings suggest remarkable plasticity and robustness of
language in spite of brain lesions that would devastate an adult's
Children with a hearing loss, either from birth or acquired during the
first year or two of life, generally have a serious delay in spoken
language development. The hearing loss occurs despite very early diagnosis
and fitting with appropriate hearing aids. However, in the unusual case
that sign language is the medium of communication in the
rather than speech, the child shows no delay in learning to use that
language. Hearing development is always one of the first things checked if
a pediatrician or parent suspects a
. The deaf child exposed only to speech will usually begin to babble
("baba, gaga") at a slightly later point than the hearing
child. Recent work suggests that the babbling is neither as varied nor as
sustained as in hearing children. However, there is often a long delay
until the first words are spoken, sometimes not until age two years or
Depending on the severity of the hearing loss, the stages of early
language development are also quite delayed. It is not unusual for the
profoundly deaf child at age four or five years to only have two-word
spoken sentences. It is only on entering specialized training programs for
oral language development that the profoundly deaf child begins to acquire
more spoken language. Often, such children do not make the usual
language gains until they reach grade school. Many deaf children learning
English have pronounced difficulties in articulation and speech quality,
especially if they are profoundly deaf, since they get no feedback in how
they sound. A child who has hearing for the first few years of life has an
enormous advantage in speech quality and oral language learning over a
child who is deaf from birth or within his or her first year.
Apart from speech difficulties, deaf children learning English often show
considerable difficulty with the
inflection and syntax of the language, which marks their writing as well
as their speech. The ramifications of this delayed language are also
significant for learning to read, and reading proficiently. The average
deaf high school student often only reads at fourth grade level.
can also affect the age at which children learn to talk. A mentally
retarded child is defined as one who falls in the lower end of the range
, usually with an IQ (intelligence quotient) below 80 on some standardized
IQ tests. There are many causes of mental retardation, including
identified genetic syndromes such as
fragile X syndrome
Retardation can also be caused by damage to the fetus during pregnancy due
to alcohol, drug abuse or toxicity, and disorders of the developing
nervous system such as
. Finally, there are environmental causes following birth such as
, anoxia, or
Any of these situations is likely to slow down the child's rate of
development in general, and thus to have effects on language development.
However, most children with very low IQs develop some language, suggesting
it is a relatively "buffered" system that can survive a good
deal of insult to the developing brain. In cases of hydrocephalus, for
example, it has been noted that children who are otherwise quite impaired
intellectually can have impressive conversational language skills.
Sometimes called the "chatterbox syndrome," this linguistic
sophistication belies their poor ability to deal with the world. In an
extreme case, a young man with a tested IQ in the retarded range has an
apparent gift for acquiring foreign languages, and could learn a new one
with very little exposure. For example, he could do fair translations at a
rapid pace from written languages as diverse as Danish, Dutch, Hindi,
Polish, French, Spanish, and Greek. He is, in fact, a savant in the area
of language, and delights in comparing linguistic systems, although he
does not have the mental capacity to live independently.
Adults should not consider retarded children to be a uniform class;
different patterns can arise with different syndromes. For example, in
hydrocephalic children and Williams syndrome, language skills may be
preserved to a degree greater than their general intellectual level. In
other groups, including Down syndrome, there may be more delay in language
than in other mental abilities.
Most retarded children babble during the first year and develop their
first words within a normal time span, but are then slow to develop
sentences or a varied vocabulary. Vocabulary size is one of the primary
components of standardized tests of verbal intelligence, and it grows
slowly in retarded children. Nevertheless, the process of vocabulary
development seems quite similar: retarded children also learn words from
context and by incidental learning, not just by direct instruction.
Grammatical development, though slow, comes in the same way, and in the
same order, as it does for normal IQ children. The child's
conversation, however, may contain more repetition. The Down syndrome
adolescent with an IQ of around 50 points does not seem to progress beyond
the grammatical level of the normally intelligent child at three years,
with short sentences that are restricted in variety and complexity.
Children with Down syndrome are also particularly delayed in speech
development. This is due in part to the facial abnormalities that
characterize this syndrome, including a relatively large tongue. It is
also linked to the higher risk they appear to suffer from ear infections
and hearing loss.
Specific language impairment
describes a condition of markedly delayed language development in the
absence of any apparent handicapping conditions such as deafness,
, or mental retardation. Specific language impairment (SLI) is also
sometimes called childhood dysphasia, or developmental language disorder.
Children with SLI usually begin to talk at approximately the same age as
normal children, but are markedly slower in their progress. They seem to
have particular problems with inflection and word forms, such as leaving
off endings when forming verb tenses (for example, the -ed ending when
forming the past tense). This problem can persist much longer than early
childhood, often into grade school and beyond, where these children
encounter difficulties in reading and writing. The child with SLI often
has difficulties learning language "incidentally," (picking
up the meaning of a new word from context or generalizing a new syntactic
form). This is in contrast to the normal child's development, where
incidental learning and generalization are the hallmarks of language
acquisition. Children with SLI are not cognitively impaired and are not
withdrawn or socially aloof like the autistic child.
Very little is known about the cause or origin of specific language
impairment, although evidence is growing that the underlying condition may
be a form of brain abnormality. However, any such brain abnormality is not
readily apparent with existing diagnostic technologies. When compared to
other children, SLI children do not
Speech therapists help children overcome their speech and language
(© Bob Rowan; Progressive Image/Corbis.)
have clear brain lesions or marked anatomical differences in either brain
About one in six people, or 42 million individuals in the United States,
have some type of communication disorder. About 28 million have speech,
voice, or language problems associated with hearing loss, and about 14
million have similar problems not associated with impaired hearing. More
than one million children in special education classes are categorized as
having a speech or language disability.
Causes and symptoms
Language disorders can arise at many points in the language production
process such as:
Symptoms of language disorders vary widely, but include:
Parents should talk to their pediatrician immediately if their child
appears to have
. They should also consult with their doctor if the child does not babble
or begin to use single words within the normal time frame. Parents of
older children may need a referral to a speech and language specialist if
their child stutters, lisps, has difficulty forming words or producing
coherent speech, or exhibits certain learning disabilities.
Speech and language disorders are usually diagnosed by a speech and
language pathologist, often with the help of a pediatrician, audiologist
(hearing specialist), and neurologist. Many
tests are designed specifically for use in children, including the
Clinical Evaluation of Language Fundamentals (also available in Spanish);
the Preschool Language Scale (also available in Spanish); the Test of
Language Development, Primary; and the Test of Language, Intermediate.
There are assessments designed to evaluate speech production, such as the
Goldman-Fristoe test of Articulation.
Treatment varies, depending on the type and cause of the language
disorder. However, in all language disorders and delays, early
intervention is key to improvement. Many educators of the deaf now urge
early compensatory programs in signed languages, because the deaf child
shows no handicap in learning a visually based language. Deaf children
born to signing parents begin to "babble" in sign at the
same point in infancy that hearing infants babble speech, and proceed from
there to learn a fully expressive language. However, only 10 percent of
deaf children are born to deaf parents, so hearing parents must show a
commitment and willingness to learn sign language. Furthermore, command of
at least written English is still a necessity for such children to be able
to function in the larger community.
Speech therapy can be a considerable aid to many children with language
disorders For example, it can help to make a Down syndrome child's
speech more intelligible. Despite the delay, children with Down syndrome
are often quite sociable and interested in language for conversation.
Surgery, followed by speech therapy, can correct physical deformities,
such as cleft palate, that interfere with speech production.
Psychotherapy can help older children whose language disorders are
Prognosis varies on an individual basis, depending on the cause, type, and
severity of the language disorder. Those children who receive early
intervention therapies are more likely to have a better outcome than those
for whom services are delayed.
Many language disorders are not preventable. However, those that arise
from damage to the fetus due to the mother's use of drugs or
alcohol during pregnancy can be prevented by avoiding these substances.
—An individual certified by the American Speech-Language-Hearing
Association (ASHA) to treat speech disorders.
Bahr, Diane Chapman.
Oral Motor Assessment and Treatment: Ages and Stages.
Boston: Allyn and Bacon, 2001.
Freed, Donald B.
Motor Speech Disorders: Diagnosis & Treatment.
San Diego: Singular Pub. Group, 2000.
Conti-Ramsden, Gina. "Processing and Linguistic Markers in Young
Children with Specific Language Impairment."
Journal of Speech, Language, and Hearing Research
46, no. 5 (October 2003): 1029–38.
Fujiki, Martin, et al. "The Relationship of Language and Emotion
Regulation Skills to Reticence in Children with Specific Language
Journal of Speech,
Language, and Hearing Research
47, no. 3 (June 2004): 637–47.
Nation, Kate, et al. "Hidden Language Impairments in Children:
Parallels Between Poor Reading Comprehension and Specific Language
Journal of Speech, Language, and Hearing Research.
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American Speech-Language-Hearing Association.
10801 Rockville Pike, Rockville, MD 20852. (800) 638-8255. Web site: