View source for Specific language impairment

{{See also|Developmental language disorder}}
{{Infobox medical condition
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| specialty = [[Neurology]], <br>[[Speech–language pathology]]
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'''Specific language impairment''' ('''SLI''') is diagnosed when a child's language does not develop normally and the difficulties cannot be accounted for by generally slow development, physical abnormality of the speech apparatus, [[autism spectrum disorder]], [[apraxia]], acquired brain damage or [[hearing loss]]. [[Twin study|Twin studies]] have shown that it is under [[Heredity|genetic]] influence. Although language impairment can result from a single-gene mutation,<ref>{{cite journal | vauthors = Lai CS, Fisher SE, Hurst JA, Vargha-Khadem F, Monaco AP | title = A forkhead-domain gene is mutated in a severe speech and language disorder | journal = Nature | volume = 413 | issue = 6855 | pages = 519–23 | date = October 2001 | pmid = 11586359 | doi = 10.1038/35097076 | bibcode = 2001Natur.413..519L | hdl = 11858/00-001M-0000-0012-CB9C-F | s2cid = 4421562 | hdl-access = free }}</ref> this is unusual. More commonly SLI results from the combined influence of multiple genetic variants, each of which is found in the general population, as well as environmental influences.<ref>{{cite journal | vauthors = Bishop DV | title = The role of genes in the etiology of specific language impairment | journal = Journal of Communication Disorders | volume = 35 | issue = 4 | pages = 311–28 | date = 2002-07-01 | pmid = 12160351 | doi = 10.1016/S0021-9924(02)00087-4 }}</ref>

==Classification==
Specific language impairment (SLI) is diagnosed when a child has delayed or disordered language development for no apparent reason.<ref name = "Bishop_2008">{{cite book | vauthors = Bishop D, Norbury CF | chapter = Speech and language impairments | veditors = Thapar A, Rutter M, Bishop D, Pine D, Scott SM, Stevenson J, Taylor E |title=Rutter's Child and Adolescent Psychiatry |publisher=Wiley-Blackwell |location=Oxford |year=2008 |pages=782–801 |isbn=978-1-4051-4549-7 |oclc=473789535}}</ref> Usually the first indication of SLI is that the child is later than usual in starting to speak and subsequently is delayed in putting words together to form sentences. [[Spoken language]] may be immature. In many children with SLI, understanding of [[language]], or ''receptive'' language, is also impaired, though this may not be obvious unless the child is given a formal assessment.<ref>{{cite book | vauthors = Bishop D |title=Uncommon understanding: development and disorders of language comprehension in children |publisher=Psychology Press |location=East Sussex |year=1997 |isbn=978-0-86377-260-3 |oclc=776282908 |url-access=registration |url=https://archive.org/details/uncommonundersta0000bish }}</ref>

Although difficulties with use and understanding of complex sentences are a common feature of SLI, the diagnostic criteria encompass a wide range of problems, and for some children other aspects of language are problematic (see below). In general, the term SLI is reserved for children whose language difficulties persist into school age, and so it would not be applied to toddlers who are late to start talking, most of whom catch up with their peer group after a late start.<ref>{{cite book | first1 = Donna J. | last1 = Thal | first2 = Jeanette | last2 = Katich |chapter=Predicaments in early identification of specific language impairment : does the early bird always catch the worm? |title=Assessment of Communication and Language (Communication and Language Intervention Series) | veditors = Thal DJ, Cole KN, Dale PS |publisher=Brookes Publishing Company |year=1996 |pages=[https://archive.org/details/assessmentofcomm0000unse/page/1 1–28] |isbn=978-1-55766-193-7 |oclc=34772171 |chapter-url=https://archive.org/details/assessmentofcomm0000unse/page/1 }}</ref>

===Terminology===
The terminology for children's language disorders is extremely wide-ranging and confusing, with many labels that have overlapping but not necessarily identical meanings. In part this confusion reflects uncertainty about the boundaries of SLI, and the existence of different subtypes. Historically, the terms "developmental dysphasia" or "developmental aphasia" were used to describe children with the clinical picture of SLI.<ref>{{cite journal | vauthors = Ingram TT, Reid JF | title = Developmental aphasia observed in a department of child psychiatry | journal = Archives of Disease in Childhood | volume = 31 | issue = 157 | pages = 161–72 | date = June 1956 | pmid = 13328151 | pmc = 2011959 | doi = 10.1136/adc.31.157.161 }}</ref> These terms have, however, largely been abandoned, as they suggest parallels with adult acquired [[aphasia]]. This is misleading, as SLI is not caused by brain damage.{{citation needed|date=August 2021}}

Some synonyms currently in use for specific language impairment are language impairment, developmental language delay (DLD), language disorder, and language-learning disability. Researcher [[Bonnie Brinton]] argues that the term "specific language impairment" is misleading because the disorder does not only affect language, but also affects reading, writing, and social/pragmatics.<ref>{{cite journal | vauthors = Fujiki M, Spackman MP, Brinton B, Hall A | title = The relationship of language and emotion regulation skills to reticence in children with specific language impairment | journal = Journal of Speech, Language, and Hearing Research | volume = 47 | issue = 3 | pages = 637–46 | date = June 2004 | pmid = 15212574 | doi = 10.1044/1092-4388(2004/049) }}</ref>

In medical circles, terms such as ''specific developmental language disorder'' are often used, but this has the disadvantage of being wordy, and is also rejected by some people who think SLI should not be seen as a "disorder". In the [[Education in the United Kingdom|UK educational system]], ''speech, language and communication needs'' (SLCN) is currently the term of choice, but this is far broader than SLI, and includes children with speech and language difficulties arising from a wide range of causes.{{citation needed|date=August 2021}}

===Subtypes (Rapin and Allen 1987)===
Although most experts agree that children with SLI are quite variable, there is little agreement on how best to subtype them.<ref>{{cite book | vauthors = Bishop DV | chapter=Specific language impairment: diagnostic dilemma | veditors = Van Balkom H, Verhoeven, LT |title=Classification of developmental language disorders: theoretical issues and clinical implications |publisher=Lawrence Erlbaum |location=Hillsdale, N.J |year=2004 |pages= 309–326 |isbn=978-1-4106-0902-1 |oclc=53721852}}</ref> There is no widely accepted classification system. In 1983 [[Isabelle Rapin|Rapin]] and Allen<ref>{{cite book | vauthors = Rapin I, Allen D | date = 1983 | chapter = Developmental language disorders: nosologic considerations. | veditors = Kirk U | title = Neuropsychology of language, reading, and spelling | pages = 155–184 | location = New York | publisher = Academic Press }}</ref> proposed a classification of developmental language disorders based on the [[Linguistics|linguistic]] features of language impairment, which was subsequently updated by Rapin.<ref>{{cite journal | vauthors = Rapin I | title = Practitioner review: developmental language disorders: a clinical update | journal = Journal of Child Psychology and Psychiatry, and Allied Disciplines | volume = 37 | issue = 6 | pages = 643–55 | date = September 1996 | pmid = 8894945 | doi = 10.1111/j.1469-7610.1996.tb01456.x }}</ref> Rapin is a child neurologist, and she refers to different subtypes as "syndromes"; many of those coming from the perspective of education or [[Speech-Language Pathology|speech-language therapy]] reject this kind of medical label, and argue that there is not a clear dividing line between SLI and normal variation.<ref>{{cite journal | vauthors = Dale PS, Cole KN | title = What's normal? Specific language impairment in an individual differences perspective | date = April 1991 | volume = 22 | issue = 2 | pages = 80–83 | doi = 10.1044/0161-1461.2202.80 | journal = Language, Speech, and Hearing Services in Schools }}</ref> Also, although most experts would agree that children with characteristics of the Rapin subtypes can be identified, there are many cases who are less easy to categorise, and there is also evidence that categorisation can change over time.<ref>{{cite journal | vauthors = Conti-Ramsden G, Botting N | title = Classification of children with specific language impairment: longitudinal considerations | journal = Journal of Speech, Language, and Hearing Research | volume = 42 | issue = 5 | pages = 1195–204 | date = October 1999 | pmid = 10515515 | doi = 10.1044/jslhr.4205.1195 }}</ref>

Rapin's subgroups fall into three broad categories:

====Receptive/expressive developmental language disorder====
Receptive/expressive phonologic/syntactic deficit syndrome is the most common form of SLI, in which the child's most obvious problems are a tendency to speak in short, simplified sentences, with omission of some [[Grammar|grammatical]] features, such as past tense -ed.<ref>{{cite book | last = Leonard | first = Laurence B. | name-list-style = vanc |title=Children with specific language impairment |publisher=The MIT Press |location=Cambridge, Mass |year=1998 |isbn=978-0-585-27859-9 |oclc=45728290 }}</ref> It is common also to see simplified [[speech production]] when the child is young. For instance, clusters of [[consonant]]s may be reduced, so that "string" is pronounced as "ting". Vocabulary is often limited, with a tendency to use "general all-purpose" terms, rather than more specific words.<ref name="RiceBode1993">{{cite journal| vauthors = Rice ML, Bode JV |title=GAPS in the verb lexicons of children with specific language impairment|journal=First Language|volume=13|issue=37|year=1993|pages=113–131 |issn=0142-7237 |doi=10.1177/014272379301303707|s2cid=144261715}}</ref><ref>{{cite journal | vauthors = Leonard LB | title = Is expressive language disorder an accurate diagnostic category? | journal = American Journal of Speech-Language Pathology | volume = 18 | issue = 2 | pages = 115–23 | date = May 2009 | pmid = 19029534 | pmc = 2718760 | doi = 10.1044/1058-0360(2008/08-0064) }}</ref>

[[Auditory verbal agnosia|Verbal auditory agnosia]] is a very rare form of language impairment, in which the child appears unable to make sense of speech sounds. It typically occurs as a symptom of [[Landau-Kleffner syndrome]], in which case a diagnosis of SLI would not be appropriate, as there is a known neurological origin of the language difficulties.

====Expressive developmental language disorder syndromes====
[[Developmental verbal dyspraxia|Developmental verbal dyspraxia (DVD)]] – in the child with DVD, comprehension is adequate; the onset of speech is very delayed and extremely limited with impaired production of speech sounds and short utterances. The poor speech production cannot be explained in terms of structural or neurological damage of the [[Speech organ|articulators]]. There is much disagreement about diagnostic criteria, but the label most often used for children whose intelligibility declines markedly when they attempt complex utterances, compared to when they are producing individual sounds or [[syllable]]s.{{citation needed|date=August 2021}}

Another key feature is inconsistency of speech sound production from one occasion to another. Although the term "[[Developmental coordination disorder|dyspraxia]]" suggests a pure output disorder,<ref name="Hill EL 2001 149–71">{{cite journal | vauthors = Hill EL | title = Non-specific nature of specific language impairment: a review of the literature with regard to concomitant motor impairments | journal = International Journal of Language & Communication Disorders | volume = 36 | issue = 2 | pages = 149–71 | year = 2001 | pmid = 11344592 | doi = 10.1080/13682820010019874 | url = http://research.gold.ac.uk/2592/1/hill_ijlcd_2001.pdf }}</ref> many – perhaps all – of these children have difficulty in doing tasks that involve mentally manipulating speech sounds, such as [[phonological awareness]] tasks. Children with DVD also typically have major literacy problems, and [[receptive language]] levels may be poor on tests of [[vocabulary]] and grammar.<ref>{{cite book | vauthors = Wells B, Stackhouse J |title=Children's speech and literacy difficulties: a psycholinguistic framework |publisher=Singular Pub. Group |location=San Diego, Calif |year=1997 |isbn=978-1-86156-030-8 |oclc=246491090 }}</ref>

Phonologic programming deficit syndrome – the child speaks in long but poorly intelligible utterances, producing what sounds like [[neologism|jargon]]. Outside Rapin's group, little has been written about this subtype, which is not generally recognised in diagnostic frameworks.{{citation needed|date=August 2021}}

====Higher order processing disorders====
Lexical deficit disorder – the child has word finding problems and difficulty putting ideas into words. There is poor comprehension for connected speech. Again, there is little research on this subtype, which is not widely recognised.

[[Pragmatic language impairment]] – the child speaks in fluent and well-formed utterances with adequate articulation; content of language is unusual; comprehension may be over-literal and language use is odd. The child may chatter incessantly and be poor at turn-taking in conversation and maintaining a topic. There has been a great deal of controversy about this category, which is termed ''pragmatic language impairment (PLI)'' in the UK. Debate has centred over the question of whether it is a subtype of SLI, part of the autistic spectrum, or a separate condition.<ref>{{cite book | vauthors = Bishop DV | date = 2000 | chapter = Pragmatic language impairment: a correlate of SLI, a distinct subgroup, or part of the autistic continuum? | veditors = Bishop DV, Leonard LB | title = Speech and Language Impairments in Children: Causes, Characteristics, Intervention and Outcome | pages = 99–113 | location = Hove, UK | publisher = Psychology Press}}</ref> In DSM-5, the term ''Social Communication Disorder'' has been introduced; this is equivalent to PLI.

===Relationship with other neurodevelopmental disorders===
Although textbooks draw clear boundaries between different neurodevelopmental disorders, there is much debate about overlaps between them.<ref>{{cite book | vauthors = Bishop D, Rutter M | year = 2008 | chapter = Neurodevelopmental disorders: conceptual approaches. | veditors = Thapar A, Rutter M, Bishop D, Pine D, Scott SM, Stevenson J, Taylor E | title = Rutter's Child and Adolescent Psychiatry | pages = 32–41 | location = Oxford | publisher = Blackwell }}</ref> Many children with SLI meet diagnostic criteria for [[dyslexia|developmental dyslexia]],<ref>{{cite journal | vauthors = Bishop DV, Snowling MJ | title = Developmental dyslexia and specific language impairment: same or different? | journal = Psychological Bulletin | volume = 130 | issue = 6 | pages = 858–86 | date = November 2004 | pmid = 15535741 | doi = 10.1037/0033-2909.130.6.858 | s2cid = 5448296 }}</ref> and others have features of [[autism]].<ref>{{cite book | vauthors = Bishop DV | date = 2008 | chapter = Specific language impairment, dyslexia, and autism: Using genetics to unravel their relationship. | veditors = Norbury CF, Tomblin JB, Bishop DV | title = Understanding developmental language disorders: from theory to practice | pages = 67–78 | location = Hove | publisher = Psychology Press }}</ref>

==Presentation==
===Associated factors===
Males are more affected by SLI than females. In clinical samples, the sex ratio of affected males: females is around 3 or 4:1.<ref name="Robinson_1991">{{cite journal | vauthors = Robinson RJ | title = Causes and associations of severe and persistent specific speech and language disorders in children | journal = Developmental Medicine and Child Neurology | volume = 33 | issue = 11 | pages = 943–62 | date = November 1991 | pmid = 1720749 | doi = 10.1111/j.1469-8749.1991.tb14811.x | s2cid = 7412606 }}</ref> The reason for this association is not known: no linkage has been found to [[genes]] on the [[sex chromosomes]].
Poor [[motor skills]] are commonly found in children with SLI.<ref name="Hill EL 2001 149–71"/> [[Brain scans]] do not usually reveal any obvious abnormalities in children with SLI, although quantitative comparisons have found differences in brain size or relative proportions of [[White matter|white]] or [[grey matter]] in specific regions.<ref>{{cite journal | vauthors = Jernigan TL, Hesselink JR, Sowell E, Tallal PA | title = Cerebral structure on magnetic resonance imaging in language- and learning-impaired children | journal = Archives of Neurology | volume = 48 | issue = 5 | pages = 539–45 | date = May 1991 | pmid = 2021369 | doi = 10.1001/archneur.1991.00530170103028 | url = http://www.escholarship.org/uc/item/1kr662bf }}</ref> In some cases, unusual brain [[gyri]] are found.<ref>{{cite journal | vauthors = Jackson T, Plante E | title = Gyral morphology in the posterior Sylvian region in families affected by developmental language disorder | journal = Neuropsychology Review | volume = 6 | issue = 2 | pages = 81–94 | date = June 1996 | pmid = 8976499 | doi = 10.1007/bf01875369 | s2cid = 30948122 }}</ref> To date, no consistent "[[neural signature]]" for SLI has been found. Differences in the brains of children with SLI vs typically developing children are subtle and may overlap with atypical patterns seen in other [[neurodevelopmental disorders]].<ref>{{cite journal | vauthors = Herbert MR, Kenet T | title = Brain abnormalities in language disorders and in autism | journal = Pediatric Clinics of North America | volume = 54 | issue = 3 | pages = 563–83, vii | date = June 2007 | pmid = 17543910 | doi = 10.1016/j.pcl.2007.02.007 }}</ref><ref>{{cite journal | vauthors = Bishop DV | title = Overlaps between autism and language impairment: phenomimicry or shared etiology? | journal = Behavior Genetics | volume = 40 | issue = 5 | pages = 618–29 | date = September 2010 | pmid = 20640915 | pmc = 2921070 | doi = 10.1007/s10519-010-9381-x }}</ref>

==Genetic==
It is now generally accepted that SLI is a strongly [[genetic disorder]].<ref>{{cite journal | vauthors = Bishop DV | title = What Causes Specific Language Impairment in Children? | journal = Current Directions in Psychological Science | volume = 15 | issue = 5 | pages = 217–221 | date = October 2006 | pmid = 19009045 | pmc = 2582396 | doi = 10.1111/j.1467-8721.2006.00439.x }}</ref> The best evidence comes from studies of twins. Two [[twins]] growing up together are exposed to the same home environment, yet may differ radically in their language skills. Such different outcomes are, however, seen almost exclusively in fraternal (non-identical) twins, who are genetically different. Identical twins share the same genes and tend to be much more similar in language ability.

There can be some variation in the severity and persistence of SLI in identical twins, indicating that environmental factors affect the course of disorder, but it is unusual to find a child with SLI who has an identical twin with normal language.

SLI is not usually caused by a [[mutation]] in a single gene. Current evidence suggests that there are many different genes that can influence language learning, and SLI results when a child inherits a particularly detrimental combination of risk factors, each of which may have only a small effect.<ref name="Bishop_2009">{{cite journal | vauthors = Bishop DV | title = Genes, cognition, and communication: insights from neurodevelopmental disorders | journal = Annals of the New York Academy of Sciences | volume = 1156 | pages = 1–18 | date = March 2009 | issue = 1 | pmid = 19338500 | pmc = 2805335 | doi = 10.1111/j.1749-6632.2009.04419.x | bibcode = 2009NYASA1156....1B }}</ref> It has been hypothesized, however, that a mutation of the FOXP2 gene may have an influence on the development on SLI to a certain degree, as it regulates genes pertinent to neural pathways related to language.<ref name="Bishop_2009" />

Only a handful of non-genetic factors have been found selectively to impact on [[language development]] in children. Later-born children in large families are at greater risk than earlier born.<ref>{{cite book | vauthors = Garside RF, Fundudis T, Kolvin I |title=Speech retarded and deaf children : their psychological development |publisher=Academic Press |location=Boston |year=1979 |isbn=978-0-12-270150-4 |oclc=6308388 }}</ref>

Overall, genetic mutation, hereditary influences, and environmental factors may all have a role in the development and manifestation of SLI. It is important, therefore, to not associate the development to a single factor, but recognize that it is oftentimes the result of complex interactions between any or all of these factors.<ref name="Bishop_2009" />

==Diagnosis==
SLI is defined purely in behavioural terms: there is no biological test for SLI. There are three points that need to be met for a diagnosis of SLI:
* The child has language difficulties that interfere with daily life or academic progress
* Other causes are excluded: the problems cannot be explained in terms of hearing loss, general developmental delay, [[autism]], or physical difficulty in speaking
* Performance on a standardized language test (see assessment, below) is significantly below age level
There is considerable variation in how this last criterion is implemented. Tombin et al. (1996) proposed the EpiSLI criterion, based on five composite scores representing performance in three domains of language (vocabulary, grammar, and narration) and two modalities (comprehension and production). Children scoring in the lowest 10% on two or more composite scores are identified as having language disorder.<ref>{{cite journal | vauthors = Tomblin JB, Records NL, Zhang X | title = A system for the diagnosis of specific language impairment in kindergarten children | journal = Journal of Speech and Hearing Research | volume = 39 | issue = 6 | pages = 1284–94 | date = December 1996 | pmid = 8959613 | doi = 10.1044/jshr.3906.1284 }}</ref>

===Assessment===
Assessment will usually include an interview with the child's caregiver, observation of the child in an unstructured setting, a hearing test, and standardized tests of language and nonverbal ability. There is a wide range of language assessments in English. Some are restricted for use by [[Speech-Language Pathology#National approaches to speech and language pathology|speech and language professionals]] (therapists or SALTs in the UK, speech-language pathologists, SLPs, in the US and Australia).
A commonly used test battery for diagnosis of SLI is the Clinical Evaluation of Language Fundamentals (CELF). Assessments that can be completed by a parent or teacher can be useful to identify children who may require more in-depth evaluation.

The Grammar and Phonology Screening (GAPS) test is a quick (ten minute) simple and accurate screening test developed and standardized in the UK. It is suitable for children from 3;4 to 6;8 years;months and can be administered by professionals and non-professionals (including parents) alike,<ref>{{cite journal | vauthors = Gardner H, Froud K, McClelland A, van der Lely HK | title = Development of the Grammar and Phonology Screening (GAPS) test to assess key markers of specific language and literacy difficulties in young children | journal = International Journal of Language & Communication Disorders | volume = 41 | issue = 5 | pages = 513–40 | year = 2006 | pmid = 17050469 | doi = 10.1080/13682820500442644 | citeseerx = 10.1.1.110.4964 }}</ref> and has been demonstrated to be highly accurate (98% accuracy) in identifying impaired children who need specialist help vs non-impaired children.<ref>{{cite journal | vauthors = van der Lely HK, Payne E, McClelland A | title = An investigation to validate the grammar and phonology screening (GAPS) test to identify children with specific language impairment | journal = PLOS ONE | volume = 6 | issue = 7 | pages = e22432 | year = 2011 | pmid = 21829461 | pmc = 3145645 | doi = 10.1371/journal.pone.0022432 | bibcode = 2011PLoSO...622432V | doi-access = free }}</ref> This makes it potentially a feasible test for widespread screening.

The Children's Communication Checklist (CCC–2) is a parent questionnaire suitable for testing language skills in school-aged children.
Informal assessments, such as language samples, may also be used. This procedure is useful when the normative sample of a given test is inappropriate for a given child, for instance, if the child is bilingual and the sample was of monolingual children. It is also an ecologically valid measure of all aspects of language (e.g. semantics, syntax, pragmatics, etc.).

To complete a language sample, the SLP will spend about 15 minutes talking with the child. The sample may be of a conversation (Hadley, 1998), or narrative retell. In a narrative language sample, the SLP will tell the child a story using a wordless picture book (e.g. ''Frog Where Are You?'', Mayer, 1969), then ask the child to use the pictures and tell the story back.

Language samples are typically transcribed using computer software such as the systematic analysis of language software (SALT, Miller et al. 2012), and then analyzed. For example, the SLP might look for whether the child introduces characters to their story or jumps right in, whether the events follow a logical order, and whether the narrative includes a main idea or theme and supporting details.

==Intervention==
Intervention is usually carried out by speech and language therapists, who use a wide range of techniques to stimulate language learning. In the past, there was a vogue for drilling children in grammatical exercises, using [[imitation]] and [[data collection|elicitation]] methods, but such methods fell into disuse when it became apparent that there was little generalisation to everyday situations. Contemporary approaches to enhancing development of language structure are more likely to adopt 'milieu' methods, in which the intervention is interwoven into natural episodes of communication, and the therapist builds on the child's utterances, rather than dictating what will be talked about. In addition, there has been a move away from a focus solely on [[grammar]] and [[phonology]] toward [[Social Interaction Approach|interventions]] that develop children's social use of [[language]], often working in small groups that may include typically developing as well as language-impaired peers.<ref>{{cite book | vauthors = Gallagher T | date = 1996 | chapter = Social-interactional approaches to child language intervention. | veditors = Beitchman J, Cohen NJ, Konstantareas MM, Tannock R | title = Language, Learning and Behavior Disorders: Developmental, Biological and Clinical Perspectives | pages = 493–514 | location = New York | publisher = Cambridge University Press }}</ref>

Another way in which modern approaches to remediation differ from the past is that parents are more likely to be directly involved, particularly with preschool children.<ref>{{cite book | vauthors = Tannock R, Girolametto L | date = 1992 | chapter = Reassessing parent-focused intervention programs. | veditors = Warren SF, Reichle J | title = Causes and effects in communication and language intervention | pages = 49–81 | location = Baltimore MD | publisher = Paul Brooks }}</ref>

A radically different approach has been developed by [[Paula Tallal|Tallal]] and colleagues, who have devised a computer-based intervention, [[Fast ForWord]], that involves prolonged and intensive training on specific components of language and auditory processing.<ref>{{cite book | vauthors = Tallal P | date = 2000 | chapter = Experimental studies of language learning impairments: From research to remediation. | veditors = Bishop DV, Leonard LB | title = Speech and Language Impairments in Children: Causes, Characteristics, Intervention and Outcome | pages = 131–155 | location = Hove, UK | publisher = Psychology Press }}</ref> The theory underlying this approach maintains that language difficulties are caused by a failure to make fine-grained auditory discriminations in the temporal dimension, and the computerised training materials are designed to sharpen perceptual acuity.

For all these types of intervention, there are few adequately controlled trials that allow one to assess clinical efficacy.<ref>{{cite journal | vauthors = Law J, Garrett Z, Nye C | s2cid = 10725720 | title = The efficacy of treatment for children with developmental speech and language delay/disorder: a meta-analysis | journal = Journal of Speech, Language, and Hearing Research | volume = 47 | issue = 4 | pages = 924–43 | date = August 2004 | pmid = 15324296 | doi = 10.1044/1092-4388(2004/069) }}</ref> In general, where studies have been done, results have been disappointing,<ref>{{cite journal | vauthors = Glogowska M, Roulstone S, Enderby P, Peters TJ | title = Randomised controlled trial of community based speech and language therapy in preschool children | journal = BMJ | volume = 321 | issue = 7266 | pages = 923–6 | date = October 2000 | pmid = 11030677 | pmc = 27499 | doi = 10.1136/bmj.321.7266.923 }}</ref> though some more positive outcomes have been reported.<ref>{{cite book | vauthors = Bryne-Saricks MC | date = 1987 | chapter = Treatment of language disorders in children: a review of experimental studies. | veditors = Winitz H | title = Human Communication and its Disorders | pages = 167–201 | location = Norwood, N.J | publisher = Ablex Publishing }}</ref> In 2010, a systematic review of clinical trials assessing the FastForword approach was published, and reported no significant gains relative to a control group.<ref name="Strong_2011">{{cite journal | vauthors = Strong GK, Torgerson CJ, Torgerson D, Hulme C | title = A systematic meta-analytic review of evidence for the effectiveness of the 'Fast ForWord' language intervention program | journal = Journal of Child Psychology and Psychiatry, and Allied Disciplines | volume = 52 | issue = 3 | pages = 224–35 | date = March 2011 | pmid = 20950285 | pmc = 3061204 | doi = 10.1111/j.1469-7610.2010.02329.x }}</ref>

==Outcome==
Longitudinal studies indicate that problems are largely resolved by five years in around 40% of 4-year-olds with SLI.<ref>{{cite journal | vauthors = Bishop DV, Edmundson A | title = Language-impaired 4-year-olds: distinguishing transient from persistent impairment | journal = The Journal of Speech and Hearing Disorders | volume = 52 | issue = 2 | pages = 156–73 | date = May 1987 | pmid = 3573746 | doi = 10.1044/jshd.5202.156 }}</ref> However, for children who still have significant language difficulties at school entry low levels of literacy are common, even for children who receive specialist help,<ref>{{cite journal | vauthors = Catts HW, Fey ME, Tomblin JB, Zhang X | s2cid = 27888843 | title = A longitudinal investigation of reading outcomes in children with language impairments | journal = Journal of Speech, Language, and Hearing Research | volume = 45 | issue = 6 | pages = 1142–57 | date = December 2002 | pmid = 12546484 | doi = 10.1044/1092-4388(2002/093) }}</ref> and educational attainments are typically poor.<ref>{{cite journal | vauthors = Snowling MJ, Adams JW, Bishop DV, Stothard SE | title = Educational attainments of school leavers with a preschool history of speech-language impairments | journal = International Journal of Language & Communication Disorders | volume = 36 | issue = 2 | pages = 173–83 | year = 2001 | pmid = 11344593 | doi = 10.1080/13682820120976 }}</ref> Poor outcomes are most common in cases where comprehension as well as expressive language is affected.<ref>{{cite journal| vauthors = Simkin E, Conti-Ramsden G |title=Evidence of reading difficulty in subgroups of children with specific language impairment|journal=Child Language Teaching and Therapy|volume=22|issue=3|year=2006|pages=315–331|issn=0265-6590|doi=10.1191/0265659006ct310xx|s2cid=145300877}}</ref> There is also evidence that the nonverbal IQ of children with SLI decreases over the course of development.<ref>{{cite journal | vauthors = Botting N | title = Non-verbal cognitive development and language impairment | journal = Journal of Child Psychology and Psychiatry, and Allied Disciplines | volume = 46 | issue = 3 | pages = 317–26 | date = March 2005 | pmid = 15755307 | doi = 10.1111/j.1469-7610.2004.00355.x }}</ref>

SLI is associated with a high rate of [[psychiatric disorder]].<ref>{{cite book | last = Cohen | first = Nancy | name-list-style = vanc |title=Language impairment and psychopathology in infants, children, and adolescents |publisher=Sage Publications |location=Thousand Oaks |year=2001 |isbn=978-0-7619-2025-0 |oclc=45749780 }}</ref> For instance, Conti-Ramsden and Botting (2004) found that 64% of a sample of 11-year-olds with SLI scored above a clinical threshold on a questionnaire for psychiatric difficulties, and 36% were regularly bullied, compared with 12% of comparison children.<ref>{{cite journal | vauthors = Conti-Ramsden G, Botting N | title = Social difficulties and victimization in children with SLI at 11 years of age | journal = Journal of Speech, Language, and Hearing Research | volume = 47 | issue = 1 | pages = 145–61 | date = February 2004 | pmid = 15072535 | doi = 10.1044/1092-4388(2004/013) }}</ref> In the longer-term, studies of adult outcomes of children with SLI find elevated rates of unemployment, social isolation and psychiatric disorder.<ref>{{cite journal | vauthors = Clegg J, Hollis C, Mawhood L, Rutter M | title = Developmental language disorders--a follow-up in later adult life. Cognitive, language and psychosocial outcomes | journal = Journal of Child Psychology and Psychiatry, and Allied Disciplines | volume = 46 | issue = 2 | pages = 128–49 | date = February 2005 | pmid = 15679523 | doi = 10.1111/j.1469-7610.2004.00342.x }}</ref> However, most studies focused on children with severe problems, where comprehension as well as expressive language was affected. Better outcomes are found for children who have milder difficulties and do not require special educational provision.<ref>{{cite journal | vauthors = Snowling MJ, Bishop DV, Stothard SE, Chipchase B, Kaplan C | title = Psychosocial outcomes at 15 years of children with a preschool history of speech-language impairment | journal = Journal of Child Psychology and Psychiatry, and Allied Disciplines | volume = 47 | issue = 8 | pages = 759–65 | date = August 2006 | pmid = 16898989 | doi = 10.1111/j.1469-7610.2006.01631.x }}</ref>

==Prevalence==
Epidemiological surveys, in the US<ref>{{cite journal | vauthors = Tomblin JB, Records NL, Buckwalter P, Zhang X, Smith E, O'Brien M | title = Prevalence of specific language impairment in kindergarten children | journal = Journal of Speech, Language, and Hearing Research | volume = 40 | issue = 6 | pages = 1245–60 | date = December 1997 | pmid = 9430746 | pmc = 5075245 | doi = 10.1044/jslhr.4006.1245 }}</ref> and Canada,<ref>{{cite journal | vauthors = Johnson CJ, Beitchman JH, Young A, Escobar M, Atkinson L, Wilson B, Brownlie EB, Douglas L, Taback N, Lam I, Wang M | display-authors = 6 | title = Fourteen-year follow-up of children with and without speech/language impairments: speech/language stability and outcomes | journal = Journal of Speech, Language, and Hearing Research | volume = 42 | issue = 3 | pages = 744–60 | date = June 1999 | pmid = 10391637 | doi = 10.1044/jslhr.4203.744 }}</ref> estimated the prevalence of SLI in five-year-olds at around 7%. However, neither study adopted the stringent "discrepancy" criteria of the ''[[Diagnostic and Statistical Manual of Mental Disorders]]'' (DSM) or [[ICD-10]]; SLI was diagnosed if the child scored below cut-off on standardized language tests, but had a nonverbal IQ of 90 or above and no other exclusionary criteria.{{Citation needed|date=February 2025}}

==Research==
Much research has focused on trying to identify what makes language learning so hard for some children. A major divide is between theories that attribute the difficulties to a low-level problem with auditory temporal processing,<ref>{{cite journal | vauthors = Ceponiene R, Cummings A, Wulfeck B, Ballantyne A, Townsend J | title = Spectral vs. temporal auditory processing in specific language impairment: a developmental ERP study | journal = Brain and Language | volume = 110 | issue = 3 | pages = 107–20 | date = September 2009 | pmid = 19457549 | pmc = 2731814 | doi = 10.1016/j.bandl.2009.04.003 }}</ref><ref>{{cite journal | vauthors = Tallal P | title = Improving language and literacy is a matter of time | journal = Nature Reviews. Neuroscience | volume = 5 | issue = 9 | pages = 721–8 | date = September 2004 | pmid = 15322530 | doi = 10.1038/nrn1499 | s2cid = 1702681 }}</ref> and those that propose there is a deficit in a specialised language-learning system.<ref>{{cite journal | vauthors = Rice ML, Wexler K, Cleave PL | s2cid = 14673508 | title = Specific language impairment as a period of extended optional infinitive | journal = Journal of Speech and Hearing Research | volume = 38 | issue = 4 | pages = 850–63 | date = August 1995 | pmid = 7474978 | doi = 10.1044/jshr.3804.850 }}</ref><ref>{{cite journal | vauthors = van der Lely HK | title = Domain-specific cognitive systems: insight from Grammatical-SLI | journal = Trends in Cognitive Sciences | volume = 9 | issue = 2 | pages = 53–9 | date = February 2005 | pmid = 15668097 | doi = 10.1016/j.tics.2004.12.002 | s2cid = 54374098 }}</ref> Other accounts emphasise deficits in specific aspects of [[memory]].<ref>{{cite journal | vauthors = Lum JA, Gelgic C, Conti-Ramsden G | title = Procedural and declarative memory in children with and without specific language impairment | journal = International Journal of Language & Communication Disorders | volume = 45 | issue = 1 | pages = 96–107 | year = 2010 | pmid = 19900077 | pmc = 2826154 | doi = 10.3109/13682820902752285 }}</ref><ref>{{cite journal | vauthors = Ullman MT, Pierpont EI | title = Specific language impairment is not specific to language: the procedural deficit hypothesis | journal = Cortex; A Journal Devoted to the Study of the Nervous System and Behavior | volume = 41 | issue = 3 | pages = 399–433 | date = June 2005 | pmid = 15871604 | doi = 10.1016/s0010-9452(08)70276-4 | citeseerx = 10.1.1.211.8238 | s2cid = 1027740 }}</ref><ref>{{cite journal | vauthors = Montgomery JW | title = Working memory and comprehension in children with specific language impairment: what we know so far | journal = Journal of Communication Disorders | volume = 36 | issue = 3 | pages = 221–31 | year = 2003 | pmid = 12742669 | doi = 10.1016/S0021-9924(03)00021-2 }}</ref><ref>{{cite journal | vauthors = Montgomery JW, Magimairaj BM, Finney MC | title = Working memory and specific language impairment: an update on the relation and perspectives on assessment and treatment | journal = American Journal of Speech-Language Pathology | volume = 19 | issue = 1 | pages = 78–94 | date = February 2010 | pmid = 19948760 | doi = 10.1044/1058-0360(2009/09-0028) }}</ref><ref name="GathercoleBaddeley1990">{{cite journal|last1=Gathercole|first1=Susan E|last2=Baddeley|first2=Alan D | name-list-style = vanc |title=Phonological memory deficits in language disordered children: Is there a causal connection?|journal=Journal of Memory and Language|volume=29|issue=3|year=1990|pages=336–360|issn=0749-596X|doi=10.1016/0749-596X(90)90004-J }}</ref> It can be difficult to choose between theories because they do not always make distinctive predictions, and there is considerable heterogeneity among children with SLI. It has also been suggested that SLI may only arise when more than one underlying deficit is present.<ref>{{cite journal | vauthors = Coady JA, Evans JL | title = Uses and interpretations of non-word repetition tasks in children with and without specific language impairments (SLI) | journal = International Journal of Language & Communication Disorders | volume = 43 | issue = 1 | pages = 1–40 | year = 2008 | pmid = 18176883 | pmc = 5524521 | doi = 10.1080/13682820601116485 }}</ref><ref>{{cite journal | vauthors = Hsu HJ, Bishop DV | title = Grammatical Difficulties in Children with Specific Language Impairment: Is Learning Deficient? | journal = Human Development | volume = 53 | issue = 5 | pages = 264–277 | date = January 2011 | pmid = 22003258 | pmc = 3191529 | doi = 10.1159/000321289 }}</ref><ref>{{cite journal | vauthors = Bishop DV | title = Developmental cognitive genetics: how psychology can inform genetics and vice versa | journal = Quarterly Journal of Experimental Psychology | volume = 59 | issue = 7 | pages = 1153–68 | date = July 2006 | pmid = 16769616 | pmc = 2409179 | doi = 10.1080/17470210500489372 }}</ref>

== See also ==
{{div col|colwidth=22em}}
* [[Auditory processing disorder]]
* [[Dual-route hypothesis to reading aloud]]
* [[Dyslexia]]
* [[Late talker]]
* [[Language delay]]
* [[Language processing]]
* [[Linguistics]]
* [[Origin of speech]]
* [[Pragmatic language impairment]]
* [[Speech–language pathology]]
* [[Speech sound disorder]]
* [[Tip of the tongue]]
{{div col end}}

== References ==
{{reflist|2}}

== Further reading ==
* {{cite book | last = Paul | first = Rhea | name-list-style = vanc |title=Language disorders from infancy through adolescence: assessment & intervention |publisher=Mosby Elsevier |year=2007 |isbn=978-0-323-03685-6 |oclc=487807750 }}

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[[Category:Communication disorders]]
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