Grammatical morphemes

include the plural -s
(cat–cats), the possessive ’s (mom–mom’s), the past tense -ed (walk–walked), and the present progressive -ing (do–doing), to name a few. Morphology is an important
linguistic tool that not only allows us to add precision to language (e.g., “Tamika walk” vs. “Tamika had walked”), but also to expand vocabulary exponentially using a relatively small core of words (base vocabulary) and morphing them into a much
larger pool of word families (e.g., school, schools, schooling, schooled, preschool).

Syntax (form)

Syntax (form) refers to the rules of language governing the internal organization of sentences. Knowledge of the rules governing syntax enables us to readily turn the simple statement He did it into the question Did he do it?, and to embed
one simple sentence (e.g., Andre is angry) in another (e.g., Andre is not coming) to produce a complex sentence (e.g., Andre, who is angry, is not coming).

Syntax is what permits a child to produce a seemingly endless sentence by linking a series of simple sentences: This is Thomas and he is so mad at Lady and Lady goes off the siding and here comes Percy and Thomas gets out of the way and Percy is coming so
fast. In short, whereas semantics provides the meaning to utterances, syntax provides the structure. Noam Chomsky’s well-known proposition that Colorless green ideas sleep furiously illustrates the difference between semantics and syntax, in which a
sentence is devoid of meaning but conforms to sophisticated syntactic rules

...

Semantics (content)

refers to the rules of language governing the meaning of individual words and word combinations. When people produce a given word (e.g., cat) or phrase (black cat), they express a certain meaning. Semantics thus involves consideration of the meaning of various words and phrases. For instance, you know that a culprit is someone who has done something wrong; the word run
has many meanings, whereas the word stapler has only one meaning; the phrase bent over backwards has both a figurative and a literal meaning; and the words pa-
paya, banana, and kiwi go together conceptually

If you ask a person to produce
the first word that comes to mind when he or she hears the word “vehicle,” the semantic relationship among words might provoke the person to respond “car” (or, alternatively, “truck” or “tractor”). Knowledge of semantics tells you something is
wrong with the sentence linguist, Noam Chomsky produced, Colorless green ideas sleep furiously, and differentiates the meaning the words express (semantics) from
the grammar that organizes them into a sentence (syntax) (Pinker, 1994).

...

Pragmatics (use)

pertains to the rules governing language use for social purposes, and is a synonym for the term social communication. Pragmatics comprises the set of rules that govern three important aspects of the social use of
language: (a) using language for different functions or intentions (communication
intentions); (b) organizing language for discourse, including conversation; and (c)
knowing what to say and when and how to say it (social conventions). In using
language for social purposes, pragmatic rules govern linguistic, extralinguistic, and
paralinguistic aspects of communication, such as word choice, turn taking, posture,
gestures, facial expression, eye contact, proximity, pitch, loudness, and pauses.

Acquisition Rate

Faced with the task of explaining how children develop their remarkable language skills, scholars have often noted that the sheer acquisition rate of language makes it difficult to study. For instance, consider the following interaction between a mother and her 30-month-old daughter:
Tajika: Thomas the very useful engine is in the siding.
Mother: He’s in the what?
Tajika: The siding. This is the siding.
Mother: Oh, that’s the siding?
This brief interaction shows the extraordinary capacity of young children to learn and use new words at a stunning rate. Siding is a part of a train track that runs off the main course. In this vignette, Tajika has placed her miniature Thomas the Tank Engine on the siding. Her mother did not know the meaning of siding, but
Tajika clearly did

Erica Hoff, a scientist who studies early language development, stated that language development reveals the genius in all children (Hoff, 2013), whereas others have referred to infants and young children as “scientists in cribs” (Gopnik, Melt- zoff, & Kuhl, 2009). The reference to children as geniuses and young scientists is based on the fact that children acquire the complexities of language at a seemingly
miraculous rate: Although at birth children understand and use no words, withina year, they begin to understand and use several words, and by about 24 months, they have a vocabulary of several hundred words and can combine them into short sentences. Whereas the 1-year-old can say only “mama” to request something to
drink, the 3-year-old can say, “Mom, Daddy said I could have some chocolate milk and I think I’ll have it in the pink sippy cup.

...

The years of early language acquisition, from birth to about puberty, are often called a critical period (or sometimes a sensitive period) for language development

...

meaning that a window of opportunity exists during which language develops most rapidly and with the greatest ease

...

A critical period for language development also im-
plies periods of time in which the environment has particularly important impacts on language growth.
One important study of the critical period, as it applies to language development, involved research on institutionalization of infants in Romania (Nelson et al.,
2007). Institutionalized care in Romania, at least until the early 2000s, typically featured very limited stimulation of infants, in part due to the very high child-to-care-
giver ratio in such settings (Smyke et al., 2007)

...

The critical period in the human species for language development is similar to the critical periods in other species for acquisition of behaviors considered essential for survival. For instance, songbirds show a critical period for song learning, although considerable differences in the ways in which songbirds acquire songs occur among the more than 4,000 songbird species (e.g., some songbirds
require early exposure to songs for song learning, whereas others can develop song in isolation; Brenowitz & Beecher, 2005). Because only one species of Homo sapiens exists, the critical period of language development applies to all children
everywhere.

...

Universality

Universality
Language is ubiquitous among the communities of the world. Every human culture has one language, and sometimes many languages, and all are equally com-
plex. The universality of language, as Steven Pinker wrote in The Language Instinct
(1994),

The universality concept, as applied to language, suggests all persons around the world apply the same cognitive infrastructure to the task of learning language, and that this cognitive infrastructure is particularly suited to the task of developing sym-
bolic representations for objects and actions (Christiansen & Kirby, 2003). Although world languages clearly vary in their syntactic organization (e.g., some languages do not have auxiliary verbs, whereas others do; see Tomasello, 2005), the cognitive
infrastructure is the same for all languages. Therefore, the way in which children learn language, and the time points at which they achieve certai

...

...

Language is strictly a human capacity. No other animals share this aptitude; thus, human language shows species specificity. Although many nonhuman species can communicate, their communication abilities tend to be relatively iconic, such that there is a transparent relationship between what is being communicated and how
it is being communicated. One study of the communication skills of domestic dogs (Border Collies, for those interested in the details) revealed they were able to fetch an object when shown a miniature version of the object (Kaminksi, Tempelman, Call, & Tomasello, 2009). (They did less well when asked to fetch objects shown
in a photograph.) The study found domestic dogs could comprehend human communication that featured iconic signs. Although this is an interesting feat, it pales in comparison to what even very young children can do, as little is iconic about human language. For instance, a 2-year-old would have little difficulty comprehending
the phrase “Mommy will be home soon” even though it is not iconic at all

Animal communication systems differ in another important way from human communication systems, specific to its hierarchical properties. Human language provides a syntactic framework that permits the combination of ideas into larger hierarchical propositions; in fact, humans can produce an endless array of novel constructions with the tool of syntax. Although animals can learn sequences of complex actions, the hierarchical complexity of human lan-
guage far exceeds the capabilities of even the most sophisticated of nonhuman primates (Conway & Christiansen, 2001). No other animal has a communication system that provides the means for combining symbols in the way syntax al-
lows humans to use language.

....

Semanticity

Semanticity Human language allows people to represent events that are decontextualized, or removed from the present—to share what happened before this moment or what may happen after this moment. This concept is called semanticity or, alternatively,
displacement. As mentioned previously, human language has no time or space boundaries because the relationship between a referent and the language used to describe it is completely arbitrary. For instance, the word cup has no relationship to that to which it refers; the relationship is completely arbitrary. As such, a person can say the word cup without having a cup present, and other people will know to
what the person is referring. Semanticity (or displacement) is the aspect of language that allows people to represent the world to others, a remarkable capacity shared
by no other species.

Productivity

Productivity describes the principle of combination—specifically, the combination of a small number of discrete units into seemingly infinite novel creations. Productivity is a phenomenon that applies to other human activities—such as mathematics and music—as well as to language. With a relatively small set of rules governing language, humans can produce an endless number of ideas and
new constructions. For instance, humans use only a small set of sounds (speakers of GAE use about 39) and can combine these small units—according to a set of rules they know intuitively (e.g., /g/ cannot follow /l/ in English at the begin- ning of a syllable)—into an infinite number of words. Likewise, humans use a relatively small number of words and with them, can create an infinite variety of
new sentences, most of which no one has ever heard. Because of the remarkable principle of productivity, you could, right now, produce a sentence that no other person has ever uttered.

The principle of productivity is inherent in language in its earliest stages of acquisition: Children who are 18 months old and have about 50 words in their vocabulary can combine and recombine this small set of words to produce sentences that neither they nor others have ever heard. This feature of language is unique to humans because the units of nonhuman communication systems cannot be recombined to make new meanings. For instance, night monkeys have 16 communication units. These units cannot be recombined to make more than 16 possible ways to communicate because the principle of productivity does not apply

...

What are Language Differences
and Language Disorders?

For most children, language development follows a fairly invariant path. Children around the world typically begin to communicate using words around the same time (12 months), and they often begin to combine words to form two-word com- binations (e.g., daddy shoe, mommy go) by around 18 months. From that point,
they accrue thousands of words in their productive vocabulary by age 5 years and achieve an adultlike grammar well before puberty

However, although this gen- eral developmental trajectory characterizes most children, it does not describe them
all. In fact, a comparison of any two children of about the same age will reveal considerable differences in the form, content, and use of their language. Such differences relate to the language being learned, gender and temperament, and the language-learning environment. In addition, some children show mild to severe disorders in language acquisition as a result of innate genetic predispositions, developmental disability, or injury or illness. In Chapter 10, we provide a more in-depth examination of these topics.

...

Language Differences

Language difference is a general term that describes the variability among language users. Two children of exactly the same age will likely show a range of differences if their language abilities are compared. For example, they may differ in the number of words they understand, the length of their sentences, the types of words they use, and the way they share language with other people during conversation. Sometimes the differences between two individuals are subtle.

However, in other instances the differences may be more significant and may even compromise communication. For instance, consider the following descriptions of young children
in the United States:
• Lamika, a 5-year-old girl, speaks a dialect of African American English. She attends a child care center in which all the other children and her teachers speak GAE.
• Angela, a 3-year-old child with hearing loss, communicates by using Signed Exact English. She attends a special preschool for children with hearing loss, and most of her peers sign with American Sign Language.
• Jack, a 2-year-old child, is learning Spanish and English simultaneously. His family speaks both languages at home. In his preschool, which includes mostly monolingual Spanish-speaking children, he speaks primarily Spanish but some times uses the grammar of English.
• Mimi, a 3-year-old child adopted from China at age 18 months, uses fewer vocabulary words and produces shorter sentences than other children in her child care center.

These examples reveal how children (as well as adults) who live in culturally and linguistically diverse communities show variability in their language.

Dialects

are the natural variations of a language that evolve within specific
cultural or geographic boundaries. These variations affect form, content, and use.

In the United States, common dialects
include Appalachian English, African American English, and Spanish-Influenced English. Each of these dialects may show subtle to more significant variations in form, content, and use from those of the GAE dialect. This finding is also true of the dialects of English spoken around the world, including those of Great Britain,
Australia, and New Zealand

Every language includes a range of dialectal variations, and the number of dialects for a given language increases when users of a language are spread across a large geographic region, when significant geographic barriers isolate one community from other communities, or when social barriers are present within a language community. Language Diversity and Differences: African American English provides an in-depth look at the African American English dialect. We provide a more thorough discussion of language diversity and differences, including dialects

Bilingualism

Bilingualism
Although many children in the United States learn a single language (monolin- gualism), others acquire two or more languages (bilingualism). Hawaii is the only officially bilingual state (English and Hawaiian), although a number of states are
unofficially bilingual, providing services in multiple languages. This is particularly the case in cities, like the international hub of Miami, Florida, in which the population is very culturally and linguistically diverse. With such diversity increasing across the United States, it is not surprising that today, about one-fifth of Americans
speak a language other than English at home

Bilingualism is the norm in many countries, such as Belgium, where many citizens speak both French and Dutch. (There are in fact three official languages in Belgium, as some persons also speak German.) Canada is officially bilingual (English and French), and the constitution requires that services be available in both languages. India has a staggering 23 official languages, and most persons are
trilingual, speaking Hindi, English, and the language of their community. Children who are raised bilingually often show language differences not seen in children who are raised monolingually, such as interchanges between the syntax and the vocabulary of the two languages they are learning. This phenomenon is called
code switching (Muñoz, Gillam, Peña, & Gulley-Faehnle, 2003). For instance, a child who is bilingual in Spanish and English may produce a sentence in Spanish that includes an English phrase or an English sentence that reflects Spanish syntax.

...

Children who learn multiple languages can do so simultaneously or sequentially. With simultaneous bilingualism, children acquire their two languages concurrently. With sequential bilingualism, children develop one language initially, then acquire a second language later. Sequential bilingualism is relatively common for Hispanic children in the United States who learn Spanish at home but then develop English in preschool or elementary school. The English skills of a sequential

...

With simultaneous bilingualism,

children acquire their two languages concurrently

sequential bilingualism

, children develop one language initially, then acquire a second language later.

Sequential bilingualism is relatively common for
Hispanic children in the United States who learn Spanish at home but then develop English in preschool or elementary school. Spanish–English child who is bilingual in the early stages of development will differ from those of a child who learned both Spanish and English from birth, and both children may show some differences in language form, content, and use from those of monolingual English-speaking children.

Although the language a child learns has clear influences on his or her language development—for instance, the stories Chinese-speaking children produce differ in their organizational structure from those of English-speaking children (Wang & Leichtman, 2000)—all languages are approximately equal in complexity. In other words, although some differences can be seen among children as a function of the
language (or languages) they are learning, all languages use the same infrastructure of the human brain and thus are similar in complexity

...

The English language has many dialects. The term
dialect refers to natural variations in form, content,
and use within a single language. In the United
States, African American English (AAE) is a prominent
dialect used not only by some African American indi-
viduals, but also by persons of various other ethnici-
ties and races. An individual’s use of AAE is typically
influenced by the amount of contact that person has
with AAE-speaking peers rather than by his or her eth-
nic or racial heritage, a point that holds true for any
English dialect

...

Like all other English dialects, AAE is a system-
atic, rule-governed system with its own rules and
conventions that influence form, content, and use. In
every way, AAE is equivalent in its complexity to any
other English dialect (Goldstein & Iglesias, 2013). This point is important because some scholars in the past
suggested that AAE is an “impoverished” version of
English, a perspective that shows a clear lack of un-
derstanding of dialectal variations, including the fact
that all languages (and their dialects) are equivalent
in complexity. Still, in many language communities
around the world, people value and assign greater
prestige to some dialects than others.

...

In the United States, some experts contend that
speakers of AAE face risks in educational achieve-
ment because their dialect differs from the one used
most commonly in schools, sometimes called School
English (SE; Charity et al., 2004). One reason for this
risk may be a mismatch between the AAE speaker’s
representation of linguistic features and the features
prominent in the dialect of his or her teachers, which
often (but not always) is GAE (Charity et al., 2004).
Another possibility is that some teachers, particu-
larly those who speak the GAE dialect, may have a
negative bias toward pupils who speak AAE, hold-
ing lower expectations and providing less effective
instruction to these pupils. However, because some
research shows that the level of familiarity with SE
among pupils who speak AAE is associated positively
with their reading achievement (Charity et al., 2004),
practitioners must improve their understanding of how
dialectal variations both aid and inhibit children’s suc-
cess in school.

...

Gender

language impairment;

One relatively well-known fact is that girls have an advantage over boys in lan- guage development. Girls usually begin talking earlier than boys do (Karmiloff & Karmiloff-Smith, 2001) and develop their vocabulary at a faster rate than boys do in the early years of life (Rowe, Raudenbush, & Goldin-Meadow, 2012). Also,
boys are more likely to have significant difficulties with language development, or language impairment; in fact, prevalence estimates show a ratio of about 2 or 3 boys to 1 girl (Dale, Price, Bishop, & Plomin, 2003; Spinath, Price, Dale, & Plomin,
2004). Despite these apparent differences between the genders, Kovas and colleagues (2005) pointed out that gender differences in language development are relatively minor, particularly as children move beyond toddlerhood into the
preschool years

Why such gender differences in language development occur is unclear. Experts point to the possibility of both biological and environmental influences (Kovas et al., 2005). For example, parents may talk more often to girls than to boys, which would help speed language development. Alternatively, hormonal factors may contribute to these differences

Genetic Predisposition
Any preschool teacher is well aware that young children of about the same age show incredible variability in their language development. Some of this variability relates to genetic predisposition. As a complex human trait, language ability is unlikely to reside on a single gene. However, evidence points to the influence of different alleles from a set of genes on all aspects of language development, in-
cluding syntax, vocabulary, and phonology

...

Language-Learning Environment
The language-learning environment in which children are reared exerts considerable influence on their language development. Although children bring biologically endowed abilities and propensities to the language-learning task, the neural archi-
tecture that supports language acquisition is an “open genetic program” (Cartwright,
2000, p. 195)

...

neural architecture

This term means the neural architecture is calibrated on the basis
of input from the environment, or the “actual evidence” children receive from the environment, concerning the form, content, and use of the language or languages to which they are exposed (Cartwright, 2000). In short, everything the child experiences in his or her environment will help calibrate his or her language-learning
apparatus

Both genetic and environmental influences play signif-
icant roles in language development. However, iden-
tifying the exact contributions of genetic influences
relative to environmental influences can be difficult.
One way to estimate the unique influences of genetics
versus environment is twin studies, or the twin method
(Kovas et al., 2005). When monozygotic (MZ) or dizy-
gotic (DZ) twins grow up in the same household, they
are assumed to share 100% of their environmental
influences, both prenatally (in the womb) and post-
natally (in the home environment; Kovas et al., 2005).
Researchers interested in estimating the influence of
genetic versus environmental influences on language
development collect measures of language from sets
of twins, often repeatedly across time. These research-
ers use a number of sophisticated statistical tech-
niques to determine the genetic heritability of certain
language skills by comparing MZ and DZ twins. They
also can isolate environmental influences on language
by carefully controlling the amount of variability in lan-
guage skill that can be attributed to genetic influences.
One of the largest twin studies to date is the
Twins Early Development Study (TEDS), conducted

...

The environmental aspects that seem to figure most prominently in the young child’s language development are the quantity and quality of language experienced.
Quantity refers to the sheer amount of language a child experiences. Quality refers to the characteristics of the language spoken in the child’s caregiving environment: the types of words (e.g., nouns, verbs, adverbs), the construction of sentences (e.g., simple, complex, compound), the intention of sentences (e.g., directives, declara-
tives, interrogatives), and the organization and specificity of stories (e.g., emotional
expression, situational details).

...

Quantity

refers to the sheer amount of language a child experiences.

Quality

refers to the characteristics of the language spoken in the child’s caregiving environment:
the types of words (e.g., nouns, verbs, adverbs), the construction of sentences (e.g.,
simple, complex, compound), the intention of sentences (e.g., directives, declara-
tives, interrogatives), and the organization and specificity of stories (e.g., emotional
expression, situational details).

How often toddlers and preschoolers participate
in conversations with their caregivers is significantly associated with language growth in the first few years of life, indicating that sheer volume of talk is important (Zimmerman et al., 2009). However, children who are exposed to an array of com- plex sentence forms (e.g., sentences with subordinate clauses, such as That boy who
hit me is not my friend), in addition to simple sentence forms, (e.g., That boy is not my friend) will use more complex sentence forms than those used by children not exposed to such syntax (Huttenlocher, Vasilyeva, Cymerman, & Levine, 2002). In
short, characteristics of the language to which children are exposed in their prominent caregiving environments (home, preschool, etc.) contribute to the variability in
children’s language development.

...

caregiver responsiveness

Studies of infants reared in mainstream United States communities have revealed one particularly important aspect of the language-learning environment: caregiver responsiveness.

This term refers to the promptness, contingency, and ap-
propriateness of caregiver responses to children’s bids for communication throughwords or other means (Tamis-LeMonda, Bornstein, & Baumwell, 2001). Experts
contend responsiveness provides a significant aid to children’s language development because it reflects the child’s current topic of interest, and provides sensitive
input that promotes semantic and syntactic learning

Higher degrees of caregiver
responsiveness during infancy and early toddlerhood are associated with accel- erated rates of language development in children. For instance, the results of one
study revealed children of highly responsive mothers achieved the 50-word mile- stone, on average, at age 15 months, whereas children of less responsive mothers were more likely to achieve this milestone at about age 21 months (Tamis-LeMonda
et al., 2001)

...

The contribution of caregivers’ responsive and sensitive language input to children’s language development indicates quality of language input is just as important as quantity. See Theory to Practice: Children Who Are Linguistically Reticent
in the Classroom for a description of how the relation between temperament and language has influenced practice in the area of promoting linguistic interactions
with children who are reticent.

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Language Disorders
Like any complex human trait, the ability to develop language in a timely and effortless manner can be adversely influenced by heritable weaknesses in the language mechanism, as well as by the presence of certain developmental disabilities and brain injuries. Children with language impairment show significant difficulties in the development of language, typically achieving language milestones more slowly than other children, and exhibiting long-standing difficulties
with various aspects of language form, content, and use. Next, we provide abrief overview of childhood language impairment, a topic we address in more
detail in Chapter 10

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Heritable Language Impairment

Heritable Language Impairment
Children with a heritable language impairment exhibit depressed language abilities, typically with no other concomitant impairment of intellect. Because of its specificity to the functioning of language, this condition is often called specific
language impairment (SLI), and it affects about 7%–10% of children (Beitchman
et al., 1989; Tomblin et al., 1997).

SLI is the most common type of communication
impairment affecting children. It is the most frequent reason for administering early intervention and special education services to toddlers through fourth graders. Evidence suggests SLI is a heritable condition, as indicated by both twin studies and family pedigree studies (Lai, Fisher, Hurst, Vargha-Khadem, & Monaco, 2001;
Spinath et al., 2004). The results of twin studies reveal a strong likelihood for an MZ twin to have SLI if his or her twin is affected. Family pedigree studies show a strong likelihood for a child to have SLI if a parent is affected.

...

Developmental Disability

Language impairment often co-occurs with certain developmental disabilities. In such cases, language impairment is considered a secondary disorder because it results secondary to a primary cause. Common causes of a secondary language impairment include intellectual disability and autism spectrum disorder. Intellectual disability is a “condition of arrested or incomplete development of the mind, which is especially characterized by impairment of skills manifested during the developmental period”
(American Association on Mental Retardation [AAMR], 2002, p. 103)

For intellectual
disability to be diagnosed, an individual must also exhibit limitations in adaptive behavior, and the activities of daily living, such as difficulties with conceptual skills (communication, functional academics, self-direction, health and safety), social skills
(social relationships, leisure), or practical skills (self-care, home living, community participation, work; AAMR, 2002). One cause of intellectual disability is Down syndrome, which is due to a chromosomal anomaly during the initial stages of fetal
development. Whether intellectual disability occurs because of Down syndrome or other causes, it is often accompanied by significant language impairment.

...

autism spectrum dis-
order

Another type of secondary language impairment is autism spectrum disorder (ASD). ASD is an umbrella term describing a variety of developmental conditions characterized by significant difficulties in social relationships and communication with others, and restricted and repetitive behaviors. These difficulties are apparent within early childhood, but may become more apparent over time, as the demands to engage in complex communication with others increase
(American Psychiatric Association, 2013). The number of children affected by ASD has increased over the last several decades, with current estimates indicating that about 1 in 68 children have ASD (Centers for Disease Control and Prevention, 2014). Children with autism spectrum disorder usually exhibit mild to
profound secondary language impairment, and some children with this dis- ability never develop productive use of language.

The frequency with which children use language as
a tool to communicate with other people varies sub-
stantially among individual children. To some extent,
frequency relates to a child’s facility with his or her
language, but it also relates to temperament.

...

Tem- perament describes an individual’s “innate way of ap-
proaching and experiencing the world” (Kristal, 2005,
p. 5), and it is a theoretical construct of human be-
havior that helps researchers understand why some
children are bold and energetic, others are sensitive
and timid, and some are inflexible (Kristal, 2005).
Given that language development requires a child to
experience input from the environment to “calibrate”
his or her language-learning mechanisms, a reason-
able conclusion is that a child’s temperament might
influence the amount of language input he or she
experiences. For instance, a child who is bold may
solicit more language from parents and teachers,
whereas the child who is reticent and shy may solicit
less language.

...

Theoretical perspectives on the potential inter-
action of language development and temperament
suggest that an interaction occurs between these
two constructs or that they influence one another.
The results of studies on the possible interaction of
language and temperament provide support for this
theory. For example, Evans (1996) found that 18 kin-
dergartners characterized by teachers as very ret-
icent (e.g., rarely asking for assistance when it was
needed, seldom participating in class discussions)
performed more poorly than their more talkative

peers on a variety of language ability measures in
first grade. What remains unclear is whether some
children are less talkative because they have less de-
veloped language skills, or whether children with less
developed language skills are less talkative

...

developed language skills are less talkative.
Theory and research on the possibility of a
temperament–language interaction have import-
ant implications for instruction in the preschool and
kindergarten classroom, in which several important
goals include fostering children’s language skills,
promoting socialization among children, and promot-
ing children’s ability to use language for a variety of
purposes. Teachers may have difficulty helping chil-
dren who are verbally reticent achieve these goals.

..

Teachers may have difficulty helping chil-
dren who are verbally reticent achieve these goals.
One approach that has been tested for increasing
children’s language use and complexity in the pre-
school classroom is training teachers to use inter-
action-promoting responses (Cabell et al., 2011).
Examples of interaction-promoting responses include
(a) using a variety of questions, (b) inviting children
to take turns, and (c) scanning the classroom and
inviting uninvolved children to participate. Evidence
shows that when teachers use these and other lan-
guage-promoting techniques in the preschool class-
room, the children talk more and use more complex
vocabulary and grammar. Although the effects of
these techniques have not been determined spe-
cifically for children who are verbally reticent, they
provide a promising way to translate theory and re-
search on the temperament–language interaction to
inform practice.

...

A condition related to ASD is

social communication disorder (SCD)

A condition related to ASD is social communication disorder (SCD), also called pragmatic communication disor-
der (American Psychiatric Association, 2013). Individuals with SCD have particular difficulty in the use of social communication, such as following the rules of con- versation (e.g., taking turns, using eye contact) and comprehending more complex
and abstract language (e.g., understanding a joke or idiom). SCD is distinctive from ASD in that individuals typically have higher levels of language skill and do not show the restrictive and repetitive behaviors characteristic of ASD. Historically, persons with SCD may have been referred to as having “high-functioning ASD,” but in
more recent years, it is recognized that SCD is best conceptualized as a particular type of disability that is distinct from that of autism.

Brain Injury

Brain Injury
Language impairment can also occur as a function of damage or injury to the mechanisms of the brain involved with language functions. Brain injuries can occur in utero (before birth) and perinatally (during the birthing process), but
they can also occur after birth; these injuries are called acquired brain injurie

Acquired brain injuries are a leading cause of death and disability among young children. Brain damage resulting from physical trauma, particularly blunt trauma to the head, is referred to as traumatic brain injury (TBI).

..

Even though it is popularly believed that the brain of the young child can readily heal following brain injury (because of plasticity), this does not seem to be the case (Catroppa & Anderson, 2009). One possible reason for this misperception is that some young children may have delayed onset of impairment; problems sus-
tained during a brain injury may not be evident until years later, when damaged areas of the brain are applied to complex skills and activities.

...