The language difficulty is manifest by abilities substantially and quantifiably below that expected for age and significantly interfering with academic achievement, occupa- tional performance, effective communication, or socialization (Criterion B). A diagnosis of language disorder is made based on the synthesis of the individual’s history, direct clinical observation in different contexts (i.e., home, school, or work), and scores from standard- ized tests of language ability that can be used to guide estimates of severity.
A positive family history of language disorders is often present. Individuals, even chil- dren, can be adept at accommodating to their limited language. They may appear to be shy or reticent to talk. Affected individuals may prefer to communicate only with family mem- bers or other familiar individuals. Although these social indicators are not diagnostic of a language disorder, if they are notable and persistent, they warrant referral for a full lan- guage assessment. Language disorder, particularly expressive deficits, may co-occur with speech sound disorder.
Language acquisition is marked by changes from onset in toddlerhood to the adult level of competency that appears during adolescence. Changes appear across the dimensions of language (sounds, words, grammar, narratives/expository texts, and conversational skills) in age-graded increments and synchronies. Language disorder emerges during the early developmental period; however, there is considerable variation in early vocabulary acquisition and early word combinations, and individual differences are not, as single indicators, highly predictive of later outcomes. By age 4 years, individual differences in language ability are more stable, with better measurement accuracy, and are highly pre- dictive of later outcomes. Language disorder diagnosed from 4 years of age is likely to be stable over time and typically persists into adulthood, although the particular profile of language strengths and deficits is likely to change over the course of development.
Children with receptive language impairments have a poorer prognosis than those with predominantly expressive impairments. They are more resistant to treatment, and diffi- culties with reading comprehension are frequently seen.
Genetic and physiological. Language disorders are highly heritable, and family mem- bers are more likely to have a history of language impairment.
Normal variations in language. Language disorder needs to be distinguished from nor- mal developmental variations, and this distinction may be difficult to make before 4 years of age. Regional, social, or cultural/ethnic variations of language (e.g,, dialects) must be considered when an individual is being assessed for language impairment.
Hearing or other sensory impairment. Hearing impairment needs to be excluded as the primary cause of language difficulties. Language deficits may be associated with a hearing impairment, other sensory deficit, or a speech-motor deficit. When language deficits are in excess of those usually associated with these problems, a diagnosis of language disorder may be made.
Intellectual disability (intellectual developmental disorder). Language delay is often the presenting feature of intellectual disability, and the definitive diagnosis may not be made until the child is able to complete standardized assessments. A separate diagnosis is not given unless the language deficits are clearly in excess of the intellectual limitations.
Neurological disorders. Language disorder can be acquired in association with neuro- logical disorders, including epilepsy (e.gi, acquired aphasia or Landau-Kleffner syndrome).
Language regression. Loss of speech and language in a child younger than 3 years may be a sign of autism spectrum disorder (with developmental regression) or a specific neuro- logical condition, such as Landau-Kleffner syndrome. Among children older than 3 years, language loss may be a symptom of seizures, and a diagnostic assessment is necessary to exclude the presence of epilepsy (e.g., routine and sleep electroencephalogram).
Language disorder is strongly associated with other neurodevelopmental disorders in terms of specific learning disorder (literacy and numeracy), attention-deficit/hyperactiv- ity disorder, autism spectrum disorder, and developmental coordination disorder. It is also associated with social (pragmatic) communication disorder. A positive family history of speech or language disorders is often present.
Diagnostic Criteria 315.39 (F80.0)