A communication disorder is any disorder that affects an individual’s ability to comprehend, detect, or apply language and speech to engage in discourse effectively with others. The delays and disorders can range from simple sound substitution to the inability to understand or use one’s native language.

The DSM-5 categorizes five communication disorders:

• language disorder – The important characteristics of a language disorder are difficulties in learning and using language, which is caused by problems with vocabulary, grammar, and putting sentences together in a proper manner. Problems can both be receptive (understanding language) and expressive (producing language).
• speech sound disorder – Previously called phonological disorder, individuals with this disorder have problems with pronunciation and articulation of their native language.
• childhood-onset fluency disorder (stuttering) – Standard fluency and rhythm of speech is interrupted, often causing the repetition of whole words and syllables. May also include the prolongation of words and syllables, pauses within a word, and/or the avoidance of pronouncing difficult words and replacing them with easier words that the individual is better able to pronounce. This disorder causes many communication problems for the individual and may interfere with social communication and performance in work and/or school settings where communication is essential.
• social (pragmatic) communication disorder – This diagnosis describes difficulties in the social uses of verbal and nonverbal communication in naturalistic contexts, which affects the development of social relationships and discourse comprehension. The difference between this diagnosis and autism spectrum disorder is that in the latter there is also a restricted or repetitive pattern of behavior.
• unspecified communication disorder – This category is for those who have symptoms of a communication disorder but who do not meet all criteria, and whose symptoms cause distress or impairment.

Language Disorder

Language disorder, also called developmental language disorder or DLD (specifically when not caused by an intellectual development disorder) is defined purely in behavioral terms: there is no biological test. There are three points that need to be met for a diagnosis of developmental language disorder (DLD):

1. The child has language difficulties that create obstacles to communication or learning in everyday life.
2. The child’s language problems are unlikely to resolve by five years of age.
3. The problems are not associated with a known biomedical condition such as brain injury, neurodegenerative conditions, genetic conditions or chromosome disorders like Down syndrome, sensorineural hearing loss, or autism spectrum disorder or intellectual development disorder (intellectual disability).

Etiology

Developmental language disorder (DLD) is associated with aspects of the home environment, and it is often assumed that this is a causal link with poor language stimulation leading to weak language skills. Twin studies, however, show that two children in the same home environment can have very different language outcomes, suggesting we should consider other explanations for the link. 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, much more common 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 DLD in identical twins, indicating that non-genetic factors affect the course of disorder, but it is unusual to find a child with DLD who has an identical twin with typical language. Current evidence suggests that there are many different genes that can influence language learning, and DLD results when a child inherits a particularly detrimental combination of risk factors, each of which may have only a small effect. Generally, children with DLD often grow into adults who have relatively low educational attainments, and their children may share a genetic risk for language disorder.

Epidemiology

It has long been noted that males are more affected by DLD than females, with a sex ratio of affected males to females around 3:1 or 4:1. However, the sex difference is much less striking in epidemiological samples, suggesting that similar problems may exist in females but are less likely to be detected. The reason for the sex difference is not well understood. Prevalence studies have shown DLD is found in about 7% of five-year-olds, approximately one in every 15 children.

Table 1. Common Red Flags for children with Developmental Language Disorder
1 Year Old	2 Years Old	3 Years Old	4 Years Old	5 Years Old
No reaction to sound No babbling Difficulty feeding No imitation Limited use of gestures	Makes minimal attempts to communicate with gestures or words Has not spoken their first words Difficulty following simple directions Inconsistent response to “no”	Limited use of speech Incomprehensible speech Limited understanding of simple questions Difficulty naming objects Frustration related to communication	Uses only three-word phrases Speech is not understandable to parents Takes a long time to understand others Difficulty asking questions and finding words to express thoughts	Speaks only in simple sentences Speech is not understandable to teachers Difficulty answering questions Difficulty with complex directions Difficulty telling stories Difficulty with peer interactions

Treatment

Treatment is usually carried out by speech and language therapists/pathologists, who use a wide range of techniques to stimulate language learning. Contemporary approaches to enhancing development of language structure, for younger children at least, 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. Interventions for older children may be more explicit, telling the children what areas are being targeted and giving explanations regarding the rules and structures they are learning, often with visual supports. Children’s language tend to improve over time, and without controlled studies, it can be hard to know how much of observed change is down to a specific treatment. There is, however, increasing evidence that direct 1:1 intervention with a speech and language therapist/pathologist can be effective for improving vocabulary and expressive language.

Speech Sound Disorder

Speech is the act of articulating sounds and can be impaired for all kinds of reasons—a structural problem such as cleft lip and cleft palate, a neurological problem affecting motor control of the speech apparatus dysarthria, or inability to perceive distinctions between sounds because of hearing loss. Some distortions of speech sounds, such as a lisp, are commonly seen in young children. These misarticulations should not be confused with language problems, which involve the ability to select and combine linguistic elements to express meanings, and the ability to comprehend meanings.

Although speech disorders can be distinguished from language disorders, they can also co-occur. Speech sound disorder (SSD) is any problem with speech production arising from any cause. The prevalence of speech sound disorders (namely, articulation disorders or phonological disorders) in young children is 8%-9%. Five percent of U.S. children ages three through 17 have a speech disorder that lasted for a week or longer during the past 12 months.

The DSM-5 diagnostic criteria for speech sound disorder are as follows:

• A. A persistent difficulty with speech sound production interferes with speech intelligibility or prevents verbal communication of messages.
• B. The disturbance causes limitations in effective communication that interfere with social participation, academic achievement, or occupational performance, individually or in any combination.
• C. Onset of symptoms is in the early developmental period.
• D. The difficulties are not attributable to congenital or acquired conditions, such as cerebral palsy, cleft palate, deafness or hearing loss, traumatic brain injury, or other medical or neurological conditions.

Speech sound disorders may be subdivided into two primary types, articulation disorders (also called phonetic disorders) and phonemic disorders (also called phonological disorders). However, some may have a mixed disorder in which both articulation and phonological problems exist. Though speech sound disorders are associated with childhood, some residual errors may persist into adulthood.

Articulation Disorders

Articulation disorders (also called phonetic disorders, or simply artic disorders for short) are based on difficulty learning to physically produce the intended phonemes. Articulation disorders have to do with the main articulators, which are the lips, teeth, alveolar ridge, hard palate, velum, glottis, and the tongue. If the disorder has anything to do with any of these articulators, then it is an articulation disorder. There are usually fewer errors than with a phonemic disorder, and distortions are more likely (though any omissions, additions, and substitutions may also be present). They are often treated by teaching the child how to physically produce the sound and having them practice its production until it (hopefully) becomes natural. Articulation disorders should not be confused with motor speech disorders, such as dysarthria (in which there is actual paralysis of the speech musculature) or developmental verbal dyspraxia (in which motor planning is severely impaired).

Phonemic Disorders

In a phonemic disorder (also called a phonological disorders), the child is having trouble learning the sound system of the language, failing to recognize which sound-contrasts also contrast meaning. For example, the sounds /k/ and /t/ may not be recognized as having different meanings, so “call” and “tall” might be treated as homophones, both being pronounced as tall. This confusion is called phoneme collapse, and in some cases many sounds may all be represented by one sound—e.g., /d/ might replace /t/, /k/, and /g/. As a result, the number of error sounds is often (though not always) greater than with articulation disorders, and substitutions are usually the most common error. Phonemic disorders are often treated using minimal pairs (two words that differ by only one sound) to draw the child’s attention to the difference and its effect on communication.

Some children with phonemic disorders may seem to be able to hear phoneme distinctions in the speech of others but not their own. This is called the fis phenomenon based on scenario in which a speech pathologist will say, “Did you say ‘fis,’ don’t you mean ‘fish’?” To which the child responds, “No, I didn’t say ‘fis,’ I said ‘fis’.” In some cases, the sounds produced by the child are actually acoustically different, but not significantly enough for others to distinguish—because those sounds are not phonemically unique to speakers of the language.

Though phonemic disorders are often considered language disorders in that it is the language system that is affected, they are also speech sound disorders in that the errors relate to use of phonemes. This relation makes them different from specific language impairment, which is primarily a disorder of the syntax (grammar) and usage of language rather than the sound system. However, the two can coexist, affecting the same person. Other disorders can deal with a variety of different ways to pronounce consonants. Some examples are glides and liquids. Glides occur when the articulatory posture changes gradually from consonant to vowel. Liquids can include /l/ and /ɹ/ .

Mixed speech sound disorders

Phonetic and phonemic errors may coexist in the same person. In such a case, the primary focus is usually on the phonological component but articulation therapy may be needed as part of the process, since teaching a child how to use a sound is not practical if the child does not know how to produce it.

Presentation

Errors produced by children with speech sound disorders are typically classified into four categories:

• omissions: Certain sounds are not produced—entire syllables or classes of sounds may be deleted; e.g., fi’ for fish or ‘at for cat.
• additions (or epentheses/commissions): An extra sound or sounds are added to the intended word; e.g. puh-lane for plane.
• distortions: Sounds are changed slightly so that the intended sound may be recognized but sounds “wrong,” or may not sound like any sound in the language.
• substitutions: One or more sounds are substituted for another; e.g., “wabbit” for rabbit or “tow” for cow.

In a typical two-year-old child, about 50% of speech may be intelligible. A four-year-old child’s speech should be intelligible overall, and a seven-year-old should be able to clearly produce most words consistent with community norms for their age. Misarticulation of certain difficult sounds ([l], [ɹ], [s], [z], [θ], [ð], [t͡ʃ], [d͡ʒ], and [ʒ]) may be normal up to eight years old. Children with speech sound disorder have pronunciation difficulties inappropriate for their age, and the difficulties are not caused by hearing problems, congenital deformities, motor disorders or selective mutism.

Treatment

For most children, the disorder is not lifelong and speech difficulties improve with time and speech-language treatment. Prognosis is poorer for children who also have a language disorder, as a language disorder may be indicative of a learning disorder.

Childhood-Onset Fluency Disorder (Stuttering)

The DMS-5 characterizes stuttering as a childhood-onset “fluency disorder” (also known as stammering and dysphemia), and is a communication disorder in which the flow of speech is disrupted by involuntary repetitions and prolongations of sounds, syllables, words, or phrases as well as involuntary silent pauses or blocks in which the person who stutters is unable to produce sounds. Stuttering also encompasses the abnormal hesitation or pausing before speech, referred to by people who stutter as blocks, and the prolongation of certain sounds, usually vowels or semivowels. The term stuttering covers a wide range of severity, from barely perceptible impediments that are largely cosmetic to severe symptoms that effectively prevent oral communication.

The impact of stuttering on a person’s functioning and emotional state can be severe and may include fears of having to enunciate specific vowels or consonants, fears of being caught stuttering in social situations, self-imposed isolation, anxiety, stress, shame, low self-esteem, being a possible target of bullying (especially in children), having to use word substitution and rearrange words in a sentence to hide stuttering, or a feeling of “loss of control” during speech. Stuttering is sometimes popularly seen as a symptom of anxiety, but there is no direct correlation in that direction.

Stuttering is generally not a problem with the physical production of speech sounds or putting thoughts into words. Acute nervousness and stress are not thought to cause stuttering, but they can trigger stuttering in people who have the speech disorder. Living with a stigmatized disability can result in anxiety and high allostatic stress load (chronic nervousness and stress) that reduce the amount of acute stress necessary to trigger stuttering in any given person who stutters, worsening the problem in the manner of a positive feedback system; the name stuttered speech syndrome has been proposed for this condition. Neither acute nor chronic stress, however, itself creates any predisposition to stuttering. The disorder is also variable, which means that in certain situations, such as talking on the telephone or in a large group, the stuttering might be more severe or less, depending on whether or not the person who stutters is self-conscious about their stuttering. People who stutter often find that their stuttering fluctuates and that they have good days, bad days and stutter-free days. The times in which their stuttering fluctuates can be random.

Epidemiology

Almost 70 million people worldwide stutter, about 1% of the world’s population. More boys stammer than girls, in the ratio of three to four boys for every one girl, because the male hypothalamic-pituitary-adrenal (HPA) axis is more active. As males produce more cortisol than females under the same provocation, they can be tense or anxious and become repetitive.

The risk for the development of a stutter usually ends by age five, and there doesn’t appear to be any effects of race, ethnicity, culture, bilingualism, or socioeconomic status (SES) on the development and prevalence of stuttering.^[1]

Etiology

Although the exact etiology, or cause, of stuttering is unknown, both genetics and neurophysiology are thought to contribute. Children who have first-degree relatives who stutter are three times as likely to develop a stutter. However, twin and adoption studies suggest that genetic factors interact with environmental factors for stuttering to occur, and many stutterers have no family history of the disorder. There is evidence that stuttering is more common in children who also have concurrent speech, language, learning, or motor difficulties. 

Another view is that a stutter or stammer is a complex tic. This view is held for the following reasons: it always arises from the repetition of sounds or words; young children like repetition and the tenser they are feeling, the more they like this outlet for their tension—an understandable and quite normal reaction. They are capable of repeating all types of behavior. The more tension that is felt, the less one likes change. The more change, the greater can be the repetition. So, when a three-year-old finds he has a new baby brother or sister, he may start repeating sounds. The repetitions can become conditioned and automatic and ensuing struggles against the repetitions result in prolongations and blocks in his speech.

In a 2010 article, three genes were found by Dennis Drayna and his team to correlate with stuttering: GNPTAB, GNPTG, and NAGPA. Researchers estimated that alterations in these three genes were present in 9% of those who have a family history of stuttering. For some people who stutter, congenital factors may play a role. These may include physical trauma at or around birth, learning disabilities, as well as cerebral palsy. In others, there could be added impact due to stressful situations such as the birth of a sibling, moving, or a sudden growth in linguistic ability.

There is clear empirical evidence for structural and functional differences in the brains of stutterers. Research is complicated somewhat by the possibility that such differences could be the consequences of stuttering rather than a cause, but recent research on older children confirms structural differences thereby giving strength to the argument that at least some of the differences are not a consequence of stuttering. There is also evidence of differences in linguistic processing between people who stutter and people who do not. Brain scans of adult stutterers have found greater activation of the right hemisphere, which is associated with emotions, than of the left hemisphere, which is associated with speech. In addition, reduced activation in the left auditory cortex has been observed in the brains of those who stutter.  

There are many treatments and speech therapy techniques available that may help decrease speech disfluency in some people who stutter to the point where an untrained ear cannot identify a problem; however, there is essentially no cure for the disorder at present. The severity of the person’s stuttering would correspond to the amount of speech therapy needed to decrease disfluency. For severe stuttering, long-term therapy and hard work is required to decrease disfluency.

Social (Pragmatic) Communication Disorder

Social (pragmatic) communication disorder (SCD or SPCD) is a disorder where individuals have difficulties with verbal and nonverbal social communication.

The DSM-5 categorizes social (pragmatic) communication disorder (SCD) as a communication disorder within the domain of neurodevelopmental disorders, listed alongside other disorders of speech and language which typically manifest in early childhood. The DSM-5 diagnostic criteria for social communication disorder is as follows:

A. Individuals have persistent difficulties in the social use of verbal and nonverbal communication as manifested by all of the following:

• deficits in using communication for social purposes, such as greeting and sharing information, in a manner that is appropriate for the social context.
• impairment of the ability to change communication to match context or the needs of the listener, such as speaking differently in a classroom than on a playground, talking differently to a child than to an adult, and avoiding use of overly formal language.
• difficulties following rules for conversation and storytelling, such as taking turns in conversation, rephrasing when misunderstood, and knowing how to use verbal and nonverbal signals to regulate interaction.
• difficulties understanding what is not explicitly stated (e.g., making inferences) and nonliteral or ambiguous meanings of language (e.g., idioms, humor, metaphors, and multiple meanings that depend on the context for interpretation).

B. The deficits result in functional limitations in effective communication, social participation, social relationships, academic achievement, or occupational performance, individually or in combination.
C. The onset of symptoms is in the early developmental period (but deficits may not become fully manifested until social communication demands exceed limited capacities).
D. The symptoms are not attributable to another medical or neurological condition or to low abilities in the domains of word structure and grammar, and are not better explained by autism spectrum disorder, intellectual development disorder (intellectual disability), global developmental delay, or another mental disorder.

Individuals with social communication disorder (SCD) have particular trouble understanding the meaning of what others are saying, and they are challenged in using language appropriately to get their needs met and interact with others. Children with the disorder often exhibit

• delayed language development;
• language disorders (similar to the acquired disorder of aphasia) such as word search pauses, jargoning, word order errors, word category errors, verb tense errors;
• stuttering or cluttering speech;
• repeating words or phrases;
• tendency to be concrete or prefer facts to stories; and
• difficulties with
  • pronouns or pronoun reversal.
  • understanding questions.
  • understanding choices and making decisions.
  • following conversations or stories (conversations are “off-topic” or “one-sided”).
  • extracting the key points from a conversation or story; they tend to get lost in the details.
  • verb tenses.
  • explaining or describing an event.
  • understanding satire or jokes and contextual cues.
  • reading comprehension.
  • reading body language.
  • making and maintaining friendships and relationships because of delayed language development.
  • distinguishing offensive remarks.
  • organizational skills.

According to Bishop and Norbury (2002), children with SCD can have fluent, complex, and clearly articulated expressive language but exhibit problems with the way their language is used. These children typically are verbose. However, they usually have problems understanding and producing connected discourse, instead giving conversational responses that are socially inappropriate, tangential, and stereotyped. They often develop eccentric interests but not as strong or obsessional as people with autism spectrum disorders.

The current view, therefore, is that the disorder has more to do with communication and information processing than language. For example, children with SCD will often fail to grasp the central meaning or saliency of events. This then leads to an excessive preference for routine and “sameness” (seen in autism spectrum disorders), as children with SCD struggle to generalize and grasp the meaning of situations that are new; it also means that more difficulties occur in a stimulating environment than in a one-to-one setting.

A further problem caused by SCD is the assumption of literal communication. This would mean that obvious, concrete instructions are clearly understood and carried out, whereas simple but non-literal expressions such as jokes, sarcasm, and general social chatting are difficult and can lead to misinterpretation. Lies are also a confusing concept to children with SCD as it involves knowing what the speaker is thinking, intending, and truly meaning beyond a literal interpretation.

Differences between SCD and Autism

Communication problems are also part of the autism spectrum disorder; however, individuals with autism also show a restricted pattern of behavior, according to behavioral psychologists. The diagnosis of SCD can only be given if autism has been ruled out. It is assumed that those with autism have difficulty with the meaning of what is being said due to different ways of responding to social situations.

Prior to the release of the DSM-5 in 2013, SCD was not differentiated from a diagnosis of autism. However, there were a large number of cases of children experiencing difficulties with pragmatics that did not meet the criteria for autism. The differential diagnosis of SCD allows practitioners to account for social and communication difficulties that occur to a lesser degree than in children with autism. SCD is distinguished from autism by the absence of any history (current or past) of restricted/repetitive patterns of interest or behavior in SCD.

Epidemiology

More research will need to be conducted to determine the true prevalence of SCD, due to it’s overlap with ASD and the newness of the diagnosis in the DSM-5; however a population estimate suggests the rates of SCD among children is about 7.5% and affects more boys than girls by a ratio of 2.6:1. Higher prevalence rates (23–33%) have been found in those with language disorders.

Treatment for SCD

Treatments for SCD are less established than for treatments for other disorders such as autism. Similarities between SCD and some aspects of autism leads some researchers to try some treatments for autism with people with SCD.

Speech therapy can help individuals who have communication disorders. Speech and language therapy treatment focuses on communication and social interaction. Speech therapists can work with clients on communication in various settings.

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