# 03 - 6A01 Developmental speech and language disord

# 6A01 Developmental speech and language disorders

Clinical Descriptions and Diagnostic Requirements for ICD-11 Mental, Behavioural or Neurodevelopmental Disorders
Developmental speech and language disorders
Developmental speech and language disorders are characterized by difficulties in understanding 
or producing speech and language or in using language in context for the purposes of 
communication. Developmental speech of language disorders include:
6A01.0 Developmental speech sound disorder
6A01.1 Developmental speech fluency disorder
6A01.2 Developmental language disorder
6A01.Y Other specified developmental speech or language disorder
6A01.Z Developmental speech or language disorder, unspecified.
Regional, social or cultural/ethnic language variations (e.g. dialects) must be considered when an 
individual is being assessed for language abilities. For example, phonological memory tasks may 
offer a less biased assessment compared to lexical tasks. A language history documenting all the 
languages the child has been exposed to since birth can assist in determining whether individual 
language variations are better explained by exposure to multiple languages rather than a speech 
or language pathology per se.
Developmental speech sound disorder
Essential (required) features
• Persistent errors of pronunciation, articulation or phonology (i.e. how language-based 
sounds are combined in culture-typical speech) that manifest as developmentally typical 
speech sound errors that persist substantially beyond the expected age or as atypical speech 
sound errors for the language spoken (e.g. word initial consonant deletion for Englishspeaking children) are required for diagnosis.
• The onset of speech sound difficulties occurs during the early developmental period.
• Speech sound difficulties result in significant limitations in the ability to communicate due 
to reduced intelligibility of speech.
• The speech errors are not better accounted for by a disease of the nervous system affecting 
the brain, peripheral nerves or neuromusculature (e.g. cerebral palsy, myasthenia gravis); 
a sensory impairment (e.g. sensory neural deafness); or a structural abnormality (e.g. cleft 
palate) or other medical condition.
Additional clinical features
• Children with developmental speech sound disorder may exhibit delays in the acquisition, 
production and perception of spoken language.
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Neurodevelopmental disorders
• Phonological speech sound errors may be consistent or inconsistent. They often involve 
classes of sounds (e.g. incorrectly producing sounds in the same manner), a different 
place of articulation, or changes in syllable structure (e.g. deletion of final consonants or 
reducing consonant clusters to single consonants).
• If the speech errors are consistently produced, familiar listeners may be able to accommodate 
and decode the speech. However, when the rate of speech increases, even familiar listeners 
may not be able to understand the individual.
• Developmental speech sound disorder may be associated with imprecision and 
inconsistency of oral movements required for speech, especially in young children 
(also called childhood apraxia or dyspraxia of speech), resulting in difficulty producing 
sequences of speech sounds, specific consonants and vowels, and appropriate prosody 
(intonation and rhythm of speech). There may be some associated oral-motor dysfunction 
affecting early feeding, sucking and chewing, blowing, and imitating oral movements and 
speech sounds, but not with the weakness, slowness or incoordination found in dysarthria.
• Developmental speech sound disorder commonly co-occurs with other neurodevelopmental 
disorders, such as attention deficit hyperactivity disorder, developmental speech fluency 
disorder and developmental language disorder.
Boundary with normality (threshold)
• Children vary widely in the sequence and age at which they acquire speech sounds. Such 
normal variation does not reflect the presence of developmental speech sound disorder. In 
contrast, children with developmental speech sound disorder exhibit persistent problems 
that cause significant limitations in the ability to communicate due to reduced intelligibility 
of speech. Up until the age of 4 years, various speech sound errors are common among 
children with typically developing speech sound acquisition, but communication remains 
relatively intact despite these errors, relative to same-aged peers.
Course features
• Many young children with developmental speech sound disorder experience remission by 
school age. Among young children diagnosed in early childhood, up to 50–70% will exhibit 
academic difficulties throughout their schooling, even if the speech sound difficulties 
themselves have remitted.
• Compared to children and adolescents with a sole diagnosis of developmental speech 
sound disorder, those with a co-occurring developmental language disorder are more 
likely to develop other mental, behavioural and neurodevelopmental disorders such as 
anxiety and fear-related disorders or attention deficit hyperactivity disorder. They are 
also more likely to exhibit greater difficulties academically, socially and adaptively by late 
childhood and adolescence.
Neurodevelopmental disorders | Developmental speech and language disorders

Clinical Descriptions and Diagnostic Requirements for ICD-11 Mental, Behavioural or Neurodevelopmental Disorders
Developmental presentations
• Prevalence rates vary but generally decrease with age such that prevalence can be as high 
as 16% at 3 or 4 years of age, approximately 4% at 6 years of age and 3.6% by 8 years of age. 
Therefore, many preschool-aged children diagnosed with developmental speech sound 
disorder exhibit typical speech sound development by the time they begin school.
• Some children with symptoms of developmental speech sound disorder early in life may 
only experience interference with functioning when they enter school, when the demands 
of the learning environment exceed their current abilities.
• Co-occurrence of other neurodevelopment disorders is more likely among children with 
persistent developmental speech sound disorder (whose speech sound errors continue 
beyond 8 or 9 years of age). In particular, these children are more likely to develop language 
impairments and reading difficulties, and tend to experience worse outcomes.
Sex- and/or gender-related features
• Developmental speech sound disorder is more prevalent among boys, especially at younger 
ages. Early speech difficulties in girls appear more likely to resolve by school age. Gender 
differences decline with age: the ratio of boys to girls affected appears to be 2:1 or 3:1 in 
early childhood, and to decline to 1.2:1 by 6 years of age.
• Boys are more likely to experience co-occurring language impairments.
Boundaries with other disorders and conditions (differential diagnosis)
Boundary with disorders of intellectual development
Individuals with a disorder of intellectual development may exhibit impaired speech production. 
However, individuals with developmental speech sound disorder do not typically also have 
significant limitations in intellectual functioning and adaptive behaviour. If speech production 
difficulties require separate clinical attention in the context of a disorder of intellectual development, 
an additional diagnosis of developmental speech sound disorder may be assigned.
Boundary with developmental speech fluency disorder and developmental 
language disorder
Like developmental speech sound disorder, developmental speech fluency disorder and 
developmental language disorder can result in reduced intelligibility that significantly affects 
communication. Developmental speech fluency disorder is characterized by disruption of the 
normal rhythmic flow and rate of speech. Developmental language disorder is characterized by 
persistent difficulties in the acquisition, understanding, production or use of language. In contrast, 
developmental speech sound disorder is characterized by errors of pronunciation that are outside 
the limits of normal variation for chronological or developmental age.
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Neurodevelopmental disorders
Boundary with selective mutism
Selective mutism is characterized by consistent selectivity in speaking, such that a child demonstrates 
adequate speech production in specific situations (typically at home) but predictably fails to speak 
in others (typically at school). Selective mutism can occur in the presence of developmental speech 
sound disorder, and both diagnoses may be assigned if warranted.
Boundary with dysphonia
Dysphonia is characterized by abnormal voice production or absences of vocal quality, pitch, 
loudness, resonance or duration. It can be caused by voice strain or overuse, by structural laryngeal 
anomalies, or by diseases of the nervous system. It may result in the distortion of speech sounds 
due to the abnormal voice quality. In contrast, developmental speech sound disorder involves the 
omission or substitution of speech sounds and also includes distortion of speech sounds (e.g. due 
to incorrect tongue placement) rather than abnormal voice quality characteristic of dysphonia.
Boundary with dysarthria
Dysarthria is a motor speech disorder directly attributable to a disease of the nervous system or to 
either congenital or acquired brain injury. Dysarthria is characterized by difficulties with the range, 
rate, force, coordination and sustainability of movements throughout the vocal tract (i.e. trunk, 
larynx, palate, tongue, lips, jaw and face) that are required for speech. These motor difficulties 
often also cause frank difficulties in eating, drinking, swallowing or saliva control. A diagnosis of 
developmental speech sound disorder should not be assigned in these cases. Rather, a diagnosis of 
secondary speech or language syndrome should be assigned in addition to the associated medical 
condition if the speech sound difficulties are a specific focus of clinical attention.
Boundary with secondary speech or language syndrome
The diagnosis of developmental speech sound disorder should not be assigned in the presence 
of a disease of the nervous system affecting the brain, peripheral nerves or neuromusculature 
(e.g. cerebral palsy, myasthenia gravis); sensory impairment (e.g. sensory neural deafness); or 
structural impairment (e.g. cleft palate), although speech sound production difficulties may be a 
presenting feature of any of these conditions. In these cases, a diagnosis of secondary speech or 
language syndrome should be assigned in addition to the associated medical condition if the speech 
sound difficulties are a specific focus of clinical attention.
Developmental speech fluency disorder
Essential (required) features
• Frequent or pervasive disruption of the normal rhythmic flow and rate of speech 
characterized by repetitions and prolongations in sounds, syllables, words and phrases, 
as well as blocking (inaudible or silent fixations or inability to initiate sounds) and word 
avoidance or substitutions, is required for diagnosis.
• The speech dysfluency is persistent over time.
• The onset of speech dysfluency occurs during the developmental period, and speech 
fluency is markedly below what would be expected based on age.
• Speech dysfluency results in significant impairment in social communication or in 
personal, family, social, educational, occupational or other important areas of functioning.
• The speech dysfluency is not better accounted for by a disorder of intellectual development, 
a disease of the nervous system, a sensory impairment or a structural abnormality.
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Neurodevelopmental disorders | Developmental speech and language disorders

Clinical Descriptions and Diagnostic Requirements for ICD-11 Mental, Behavioural or Neurodevelopmental Disorders
Additional clinical features
• Developmental speech fluency disorder includes cluttering, in which speech tends to be 
rapid, erratic and dysrhythmic, with breakdown in fluency and clarity, often with deletion 
or collapsing of syllables and omissions of word endings.
• Developmental speech fluency disorder may be accompanied by physical tension in 
the speech musculature, as well as body tension, struggle behaviour and secondary 
mannerisms, such as facial grimacing, eye blinking, head movements, and arm and leg 
movements such as leg tapping or fist clenching.
• Developmental speech fluency disorder is often accompanied by anxiety in anticipation of 
speaking and avoidance of speaking.
• The extent of the problem varies across situations and can be more severe when there is 
pressure to communicate.
• Developmental speech fluency disorder may be associated with a broader range of speech 
and language abnormalities.
• Occasionally, onset of dysfluency can be related to a significant psychological event such 
as bereavement, and is sometimes referred to as “psychogenic stammering”. When this 
occurs during the developmental period, it may be diagnosed as developmental speech 
fluency disorder.
• Approximately 60% of children with developmental speech fluency disorder exhibit cooccurring developmental speech and language disorders.
• Among adolescents and adults with chronic speech dysfluencies, social anxiety is common 
and may exacerbate dysfluency. As many as 40–60% of these individuals meet the diagnostic 
requirements for social anxiety disorder.
Boundary with normality (threshold)
• Many typically developing children show minor dysfluencies during the preschool years.
Course features
• The course of developmental speech fluency disorder may be relatively brief in many cases, 
with the majority of children (65–85%) remitting, without intervention, prior to puberty. 
Among these children, recovery is typically within the first 2 years after onset.
• The impact of developmental speech fluency disorder may be evident as early as 3 years of 
age, with impairments in emotional, behavioural and social domains compared to typically 
developing peers.
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• A more persistent course is associated with male gender, family history of developmental 
speech fluency disorder, age at onset of greater than 3–4 years of age, duration of more 
than 1 year, and co-occurring developmental language disorder. More severe presentations 
of the disorder in childhood are more likely to persist into adolescence and adulthood.
Developmental presentations
• Developmental speech fluency disorder emerges early in the developmental period, 
typically between 2.5 and 4 years of age. Around 5–8% of preschool-aged children exhibit 
stuttering; 80–90% of cases develop by age 6, and onset after age 9 is rare. The lifetime 
incidence of stuttering is estimated at 5%, whereas population prevalence is estimated at 
approximately 1%.
• Dysfluency tends to emerge gradually and may worsen as the individual becomes aware of 
their fluency difficulty. This may lead to development of mechanisms to avoid dysfluency 
or the associated emotional discomfort, further impairing speech (e.g. avoiding public 
speaking or limiting speech to simple and short phrases).
Sex- and/or gender-related features
• Across the developmental period, boys are more commonly affected. Among preschoolaged children, the ratio of boys to girls with developmental speech fluency disorder is 
estimated at 1.5:1. However, females are more likely to remit. Throughout school age and 
into adulthood, affected males are estimated to outnumber affected females by a ratio of 4:1.
Boundaries with other disorders and conditions (differential diagnosis)
Boundary with developmental speech sound disorder and developmental language 
disorder
Like developmental speech fluency disorder, developmental speech sound disorder and 
developmental language disorder can result in reduced intelligibility that significantly affects 
communication. Developmental speech sound disorder is characterized by errors of pronunciation 
that are outside the limits of normal variation for chronological or developmental age. Developmental 
language disorder is characterized by persistent difficulties in the acquisition, understanding, 
production or use of language. In contrast, developmental speech fluency disorder is characterized 
by disruption of the normal rhythmic flow and rate of speech. If the diagnostic requirements for 
both developmental fluency disorder and another developmental speech and language disorder are 
met, both diagnoses may be assigned.
Neurodevelopmental disorders | Developmental speech and language disorders

Clinical Descriptions and Diagnostic Requirements for ICD-11 Mental, Behavioural or Neurodevelopmental Disorders
Boundary with primary tics and tic disorders, including Tourette syndrome
Dysfluency associated with other movements of the face or body that coincide in time with 
repetitions, prolongations or pauses in speech flow needs to be differentiated from complex tics. 
Tics do not involve the marked speech dysfluency that characterizes a developmental speech 
fluency disorder.
Boundary with diseases of the nervous system
Diseases of the nervous system affecting the anatomical and functional mechanisms for speech 
output can sometimes give rise to speech dysfluency, but are distinguished on examination by the 
presence of positive neurological signs.
Developmental language disorder
Essential (required) features
• Persistent deficits in the acquisition, understanding, production or use of language (spoken 
or signed) are required for diagnosis. Any of the following specific components of language 
skill may be differentially impaired, with relative weaknesses in some and relative strengths 
in others, or impairment may be more consistent across the different component skills:
• the ability to decompose words into constituent sounds and mentally manipulate those 
sounds (i.e. phonological awareness);
• the ability to use language rules – for example, regarding word endings and how words 
are combined to form sentences (i.e. syntax, morphology or grammar);
• the ability to learn, understand and use language to convey the meaning of words and 
sentences (i.e. semantics);
• the ability to tell a story or have a conversation (i.e. narrative or conversational discourse);
• the ability to understand and use language in social contexts – for example, making 
inferences, understanding verbal humour and resolving ambiguous meaning (i.e. 
pragmatics).
• Language abilities are markedly below what would be expected based on age.
• The onset of language difficulties occurs during the developmental period – typically 
during early childhood.
• Language deficits result in significant limitations in communication, with functional 
impact in daily life at home, school or work.
• The language deficits are not better accounted for by a disorder of intellectual development, 
autism spectrum disorder, another neurodevelopmental disorder, a sensory impairment, 
or a disease of the nervous system, including the effects of brain injury or infection (e.g. 
due to trauma, stroke, epilepsy or meningitis).
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Neurodevelopmental disorders
Specifiers for areas of language impairment
The main areas of language ability currently affected in developmental language disorders should 
be characterized using one of the following specifiers, although these may vary over time:
Developmental language disorder with impairment of receptive and 
expressive language
• This specifier should be applied when the ability to learn and understand spoken or signed 
language (i.e. receptive language) is markedly below the expected level for the individual’s 
age, and is accompanied by persistent impairment in the ability to produce and use spoken 
or signed language (i.e. expressive language).
Developmental language disorder with impairment of mainly expressive language
• This specifier should be applied when the ability to produce and use spoken or signed 
language (i.e. expressive language) is markedly below the expected level for the individual’s 
age, but the ability to understand spoken or signed language (i.e. receptive language) is 
relatively intact.
Developmental language disorder with impairment of mainly pragmatic language
• This specifier should be applied when the developmental language disorder is characterized 
by persistent and substantial difficulties with the understanding and use of language in 
social contexts – for example, making inferences, understanding verbal humour and 
resolving ambiguous meaning. Receptive and expressive language skills are relatively 
unimpaired, but pragmatic language abilities are markedly below the expected level for 
the individual’s age, and interfere with functional communication to a greater degree than 
with other components of language (e.g. syntax, semantics). This specifier should not be 
used if the pragmatic language impairment occurs in the context of a diagnosis of autism 
spectrum disorder.
Developmental language disorder with other specified language impairment
• This specifier should be applied if the developmental language disorder meets all the 
diagnostic requirements of the disorder but the pattern of deficits in language is not 
adequately characterized by one of the other available specifiers.
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Neurodevelopmental disorders | Developmental speech and language disorders

Clinical Descriptions and Diagnostic Requirements for ICD-11 Mental, Behavioural or Neurodevelopmental Disorders
Additional clinical features
• In typical development, understanding and production of the different components of 
language are tightly correlated and develop in tandem. In developmental language disorder, 
this developmental relationship may be out of step, with differential impairment in any of 
the component language skills.
• Many children with developmental language disorder exhibit a discrepancy between 
verbal and nonverbal ability, but this is not a requirement for diagnosis.
• Developmental language disorder frequently co-occurs with other neurodevelopmental 
disorders, such as developmental speech sound disorder, developmental learning disorder, 
attention deficit hyperactivity disorder, autism spectrum disorder and developmental 
motor coordination disorder.
• Developmental language disorder is often associated with difficulties in peer relationships, 
emotional disturbance and disruptive behaviours, particularly in school-aged children.
• Developmental language disorder often runs in families.
• Developmental language disorder can be a presenting feature in some individuals with 
specific chromosomal anomalies, including sex chromosome anomalies. Where available, 
chromosome testing can assist in identifying other health risks associated with specific 
underlying chromosomal abnormalities. If a specific chromosomal or other developmental 
anomaly is identified, this should be diagnosed in addition to the developmental 
language disorder.
• Regression of language skills once acquired is not a feature of developmental language 
disorder. Reported loss of early first words in the second year of life associated with a 
decline in social and communication behaviours – and, more rarely, loss of language skills 
after 3 years of age – may be a presentation of autism spectrum disorder. Language abilities 
may also be lost due to diseases of the nervous system including acquired brain injury 
from stroke, trauma or encephalopathy with or without overt epilepsy. Concomitant loss of 
physical skills with language abilities may be indicative of a neurodegenerative condition. 
When an underlying neurological cause has been identified, the condition should not be 
diagnosed as developmental language disorder but rather as secondary speech or language 
syndrome, which should be assigned in addition to the appropriate diagnosis for the 
underlying condition.
Boundary with normality (threshold)
• Children vary widely in the age at which they first acquire spoken language and in the pace 
at which language skills become firmly established. The majority of preschool-aged children 
who acquire speech later than expected go on to develop normal language abilities. Very 
early delays in language acquisition are therefore not indicative of developmental language 
disorder. However, the absence of single words (or word approximations) by 2 years of age, 
the failure to generate simple two-word phrases by 3 years of age, and language impairments 
that are persistent over time are more likely to indicate developmental language disorder, 
especially in the context of a known family history of language or literacy learning 
problems. By 4 years of age, individual differences in language ability are more stable.
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Neurodevelopmental disorders
• Pronunciation and language use may vary widely depending on the social, cultural and 
other environmental context (e.g. regional dialects). However, within any typical cultural 
setting, a developmental language disorder is characterized by significant deficits in 
language abilities relative to the person’s same-aged peers in the community. A bilingual 
environment is not a cause of persistent language learning impairment.
Course features
• The course of developmental language disorder may vary with the type and severity of 
symptom profile: impairment of receptive and expressive language (compared to those 
with impairment of mainly expressive language) is more likely to be persistent, and is 
associated with subsequent difficulties in reading comprehension.
• The particular pattern of language strengths and deficits may change over the course 
of development.
• Unlike developmental speech sound and speech fluency disorders, developmental 
language disorder is more likely to be maintained throughout development and into 
adulthood: approximately 75% of individuals diagnosed with developmental language 
disorder in childhood continue to meet the diagnostic requirements for the disorder 
in late adolescence. The impact of these impairments continues to be evident into early 
adulthood as behavioural, social, adaptive and communication problems, often with 
lifelong social consequences.
Developmental presentations
• Developmental language disorder emerges early in development, though it can be 
challenging to distinguish typical variations from impairments in language development 
prior to age four. Diagnosis from 4 years of age onwards tends to yield a more stable 
symptom presentation, and is more likely to be persistent.
• The prevalence of developmental language disorder among children is estimated at 6–15%, 
but is more common among children with other co-occurring neurodevelopmental 
disorders.
Sex- and/or gender-related features
• Developmental language disorder appears to affect more boys than girls, though this 
gender ratio varies across clinical and population-based samples (from 1.3:1 to 6:1).
• Boys appear to be more likely than girls to experience co-occurring developmental 
language and developmental speech sound disorders.
Neurodevelopmental disorders | Developmental speech and language disorders

Clinical Descriptions and Diagnostic Requirements for ICD-11 Mental, Behavioural or Neurodevelopmental Disorders
Boundaries with other disorders and conditions (differential diagnosis)
Boundary with disorders of intellectual development
Individuals with disorders of intellectual development may exhibit delays in language onset, or 
development or impairment in language abilities, accompanied by generalized impairment in 
intellectual and adaptive behaviour functioning. Developmental language disorder can occur with 
varying levels of intellectual ability. If the diagnostic requirements of a disorder of intellectual 
development are met and language abilities are significantly below what would be expected based on 
the general level of intellectual functioning and adaptive behaviour, both diagnoses may be assigned.
Boundary with developmental speech sound disorder and developmental speech 
fluency disorder
Like developmental language disorder with impairment in mainly expressive language, 
developmental speech sound disorder and developmental speech fluency disorder can result in 
reduced intelligibility that significantly affects communication. Developmental speech sound 
disorder is characterized by errors of pronunciation that are outside the limits of normal variation 
for chronological developmental age. Developmental speech fluency disorder is characterized by 
disruption of the normal rhythmic flow and rate of speech. In contrast, developmental language 
disorder is characterized by persistent difficulties in the acquisition, understanding, production or 
use of language.
Boundary with autism spectrum disorder
Individuals with autism spectrum disorder often present with delayed language development. The 
extent of functional language impairment, which refers to the capacity of the individual to use 
language for instrumental purposes (e.g. to express personal needs and desires), should be coded 
using the autism spectrum disorder functional language impairment specifier rather than using a 
separate diagnosis of developmental language disorder. Moreover, pragmatic language impairment 
is a characteristic feature of autism spectrum disorder even when other aspects of receptive and 
expressive speech are intact. Autism spectrum disorder is differentiated from developmental 
language disorder by the presence of additional impairments in social reciprocity as well as restricted, 
repetitive and stereotyped behaviours. Unlike individuals with autism spectrum disorder, individuals 
with developmental language disorder are usually able to initiate and respond appropriately to 
social and emotional cues and to share interests with others, and do not typically exhibit restricted, 
repetitive and stereotyped behaviours. An additional diagnosis of developmental language disorder 
should not be assigned to individuals with autism spectrum disorder based solely on pragmatic 
language impairment. However, both diagnoses may be assigned if there are additional specific 
impairments in semantic, syntactic and phonological development.
Boundary with developmental learning disorder
Persistent deficits in the acquisition, understanding, production or use of language in developmental 
language disorder may lead to academic learning difficulties, especially in literacy – including word 
reading, comprehension and written output. If all diagnostic requirements for both developmental 
language disorder and developmental learning disorder are met, both diagnoses may be assigned.
Boundary with selective mutism
Selective mutism is characterized by consistent selectivity in speaking, such that a child demonstrates 
adequate language competence in specific social situations (typically at home) but predictably fails to 
speak in others (typically at school). In contrast, language difficulties associated with developmental 
language disorder are apparent in all settings. However, selective mutism and developmental 
language disorder can co-occur, and both diagnoses may be assigned if warranted.
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Neurodevelopmental disorders
Boundary with diseases of the nervous system and sequelae of brain injury 
or infection
Language impairment may result from brain damage due to stroke, trauma, infection (e.g. meningitis/
encephalitis), developmental encephalopathy with or without overt epilepsy, or syndromes of 
regression (e.g. Landau-Kleffner syndrome or acquired epileptic aphasia). When language difficulties 
are a specific focus of clinical attention, a diagnosis of secondary speech or language syndrome 
should be assigned in addition to the associated medical condition.
Boundary with oral language delay or impairment due to hearing impairment
All children presenting with language impairment should have an assessment for hearing impairment 
because language delay may be better accounted for by hearing impairment. Very young children 
with hearing impairment usually compensate for lack of oral language by using nonverbal modes 
of communication (e.g. gestures, facial expressions, eye gaze). However, presence of hearing loss 
does not preclude a diagnosis of developmental language disorder if the language problems are 
disproportionate relative to the severity of hearing loss. Developmental language disorder can be 
assigned to children whose primary communication modality is through signing if exposure to 
and opportunity to learn sign language has been adequate and the other features of the disorder 
are present as they apply to sign language.
Boundary with other medical conditions involving loss of acquired language skills
When loss of acquired language skills occurs as a result of another medical condition (e.g. a stroke), 
and language difficulties are a specific focus of clinical attention, a diagnosis of secondary speech 
or language syndrome should be assigned in addition to the associated medical condition rather 
than a diagnosis of developmental language disorder.
Other specified developmental speech or language disorder
Essential (required) features
• Persistent difficulties in understanding or producing speech or language or in using 
language in context for the purposes of communication that are not better accounted 
for by developmental speech sound disorder, developmental speech fluency disorder, 
developmental language disorder or autism spectrum disorder are required for diagnosis.
• The speech or language difficulties are persistent over time.
• The onset of the speech or language difficulties occurs during the developmental period, 
and speech or language abilities in the affected areas are markedly below what would be 
expected based on age.
• The speech or language difficulties result in significant impairment in social communication, 
or in personal, family, social, educational, occupational or other important areas of 
functioning.
• The speech or language difficulties are not better accounted for by a disorder of intellectual 
development, a disease of the nervous system, a sensory impairment or a structural 
abnormality.
Developmental speech or language disorder, unspecified
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6A01.Z
Neurodevelopmental disorders | Developmental speech and language disorders