CHAPTER TWO
2.0 REVIEW OF
RELATED LITERATURE
2.1 Introduction
This chapter
focuses on earlier studies carried out on child’s social and language
development process. The available related literature is being reviewed under
the following sub-headings:
v
Overview
of language
v
Language Content
v
The Communication Environment
v
Developmental stages of Chilgren
v
Theories of language acquisition
v
Behaviorism
v
Innativism
v
Vygoitsky’s theory of language
v
Review of Empirical studies on Language Acquisition
2.1 Overview of
Language
Language has been hailed as the hallmark of
humanity, the ability that separates humans from animals (Berko-Gleason, 1997).
As humans in society, we use our language ability continuously to embrace
ideas, share our feelings, comment on the world, and understand each other’s
minds. Language can be defined as an organized system of arbitrary signals and
rule-governed structures that are used as a means for communication. Language
occurs both receptively and expressively through reading, listening, writing,
and speaking. In order to become fully functioning members of school and
society, children must learn the elements, the rules, the structure, and the
conventions of this system. Our working definition of language encompasses five
structural components: phonology, semantics, syntax, morphology, and
pragmatics. Phonology refers to the sounds and the intonation patterns that are
associated with spoken language. Semantics encompasses the words of a language and
the meanings associated with those words. Syntax describes the grammatical
rules of a language—how words combine into phrases and sentences. Morphology
refers to the rules that govern the use of morphemes. Morphemes are the
smallest units of meaning in a language, including the prefixes and suffixes
that mark syntactic and semantic information, such as number (i.e., plurals),
gender, and tense (i.e., past, present, or future). Finally, pragmatics is how
we adjust our speech to our audience and use language toward the goal of
communication. To better address typical and atypical language development as
well as strategies of prevention and intervention, the five structural
components of language may be simplified into three essential aspects of
communication: content, form, and use (Bloom & Lahey, 1978). Content refers
to the semantics of language—the concepts and ideas that are encoded in words.
Form is the way in which meaning is represented, including speech, sign
language, and writing. In the context of spoken language, form encompasses
phonology, morphology, and syntax.
Finally, use refers to the function of language in
context. Although each of these aspects of language can be identified separately,
they are inherently interconnected elements in communication (Bloom &
Lahey). Language problems may arise when there is a disruption within any one
component of the model or in their integration.
2.3
Language Content
Relations between words and their referents are
arbitrary and symbolic. Words themselves do not lend the language learner any
clues to the identity of what is being labeled. Thus, learning the meaning of
words involves learning how one’s own language community labels content in the
world. This is not an easy task. Consider, for example, seeing a rabbit hopping
by and hearing the word rabbit. How does one know whether the word applies to
the whole rabbit or to its fur? To its twitching whiskers or to its hopping?
Research suggests that even very young children are guided in this initial
word-to-referent mapping by a default set of assumptions or predispositions
(see Woodward & Markman, 1998, for a review of these principles). Hypotheses
based on these assumptions are then supplemented by input and feedback from
mature speakers, allowing children to test and revise their label to referent mappings
in order to conform to those of their speech community.
The semantic achievement of the production of the first
word typically occurs around the child’s first birthday; however, it may appear
as early as 8 months or as late as 16 months without indicating serious
concern. By this time, children have already been exposed to a great deal of
language and possess a receptive vocabulary of about 50 words (Fenson et al.,
1994). Once vocabulary learning begins, progress is slow and measured. However,
by 18 months of age productive vocabularies typically expand to about 50 words.
Great individual differences appear during this period. For example, although
at 16 months the average number of words a baby can say is 40, the top 10% of
16-month-olds can say 180 words, and the bottom 10% can say fewer than 10, and
in some cases none at all (Fenson et al., 1994). This variation among children
is completely normal and should be expected. During the toddler, preschool, and
school years, children continue to acquire a varied lexicon. Semantic development
expands from the concrete nouns of infancy to complex, abstract, and relational
concepts, such as words for actions, emotions, and colors; and deictic terms,
such as I, you, this, and that. Children also make connections among the words
in their vocabulary, building a complex network of interrelated words and
concepts.
Semantic development does not end in childhood. Even
into adulthood we continue to add new words to our lexicon (e.g., blog and
latte), and fine-tune the content of our communication as we increase our
knowledge and experiences (see Pan, 2001, for a review of semantic development).
2.4 The communication environment
Although there is a clear case for the role played
by social disadvantage in predicting language skills in young children, the
studies often make it difficult to disentangle precisely what it is about
children’s social backgrounds that are important for child development. For
this reason we are developing, in this present study, a model of risk which is
specifically tied to the child’s communication environment. Specifically we are
interested in what parents do to promote the communication skills of
their child, what they feel in terms of the support they receive and
what they have in terms of the materials at their disposal to facilitate
the child’s communication. Knowing, for example, that a family lives in council
rented accommodation will give some indication of material poverty but knowing
the specific resources at the disposal to the parent and child and what they do
with those resources is likely to be much more informative about the process by
which the child’s communication skills are encouraged and ultimately the
child’s preparedness for school (Locke et al, 2002). Thus we hypothesise that
the communication environment comprises:
What parents do:
aspects of the mother’s activity and interaction with the child;
What parents feel:
specifically, the mother’s feelings, attitudes and sense of wellbeing;
What parents have:
resources which are available and underpin activity with the child.
2.4.1 What parents do:
Recent analyses have tended to be circumspect about
the precise characteristics of environments which do and which do not promote
language development. Probably the most influential single study in the field
has been Hart and Risley’s study (1995) of the verbal input received by
children from different social groups. The results very clearly indicate that
the children from so called “welfare mothers” consistently received less verbal
input than children from blue collar or professional parents. Recent argument
has developed this further, using larger representative samples as their
source. For example Pan and colleagues (2005) have suggested that it is not the
amount that a mother talks to her child that predicts how their language will
subsequently develop but it is the number of word types used by the mother and
the language and literacy levels of the mother. This suggests that it is
something about the nature of those parental skills which interacts with the
communication needs of the child, specifically their sensitivity to the child
(Hoff-Ginsberg, 1995). This is supported from an analysis of the 10% “Children
in Focus” sample from the Avon Longitudinal Study of Parents and Children
(ALSPAC) cohort. Boyle and colleagues (Boyle et al submitted) suggested that
different cognitive styles, measured from clips of videoed parent/child
interaction at one year of age, are associated with parenting
behaviour and appear to be associated with different
aspects of communication development two years later.
Interestingly there is a tension developing in the
literature over when parental input plays the most significant role. While many
argue that the environment plays a role from the word go and thus that
intervention should be targeted at the earliest possible age, a recent strand
of research suggests that the influences of the parenting environment increases
as the role of “biological” factors decreases. For example, reports from
Australia’s ELVS study suggest that the variance accounted for by environmental
factors increases from less than 10% of the variance in expressive and
receptive language skills at two years to 20% by four years (Reilly et al,
2007& 2010). In short, while the social circumstances in which the child is
raised in the early years are clearly linked to early language development, it
remains unclear which specific aspects of the child’s early experiences are
most important and which are most likely to be modifiable at which time point.
Indeed it is likely that the higher level, more distal social risk factors
(such as maternal education, income or social deprivation generally) will be less
amenable to change than the more proximal factors that affect the day to day
interactions of the child with their parents and others in their immediate
environment.
2.4.2
What parents feel:
The child’s mother or primary carer, is a crucial
component of a child’s communication environment and as outlined above, the
mother has been the focus of much research investigating how she interacts with
her child in order to facilitate language development (Hart & Risley,
1995). It is the mother’s communicative behaviour that has dominated this
research (Hart & Risley, 1995; Hoff-Ginsberg, 1998) as opposed to
considering what factors may underlie this behaviour. The mother’s
communicative behaviour is very dependent on her capacity to understand the
need to interact with her child, her motivation to engage in this process and
the quality of the communication environment that she is able to provide.
Furthering our understanding of the mother’s attachment to her child can inform
us of how mothers can be supported to provide a facilitative communication
environment for her child.
Although research in this area is under-developed,
there are three factors reported in the literature that are taken to define a mother’s
capacity. These are 1) the age and experience of the mother; 2) her mental well
being and 3) her attachment to the child. Age and experience has been studied
by comparing the language abilities of children born to teenage mothers to
children of older mothers. Preliminary research suggests that the young
children of teenage mothers have poorer language abilities compared to the
children of older mothers (Keown et al, 2001). Teenage mothers are reported to
provide a communicative environment that has a negative impact on their child’s
language development by using less complex and varied
language and being more directive and less
facilitative in their actions than older mothers (Keown et al, 2001; Oxford
& Spieker, 2006). The lack of adequate measures to control for social
background and the small sample sizes compound the findings from these studies.
Nevertheless there is an important question to consider of whether the
communicative behaviour of mothers is dependent on their age and experience or even
their own language and literacy abilities (as outlined earlier), and their
communicative competence which may well not be fully developed in their teenage
years.
The impact of maternal depression on children’s
general development is well documented and is known to be a significant risk
factor for poor attachment in the first few years of a child’s life. Maternal
depression certainly limits the mother’s capacity to care for her child, to
stimulate her general development and to form a robust attachment. In contrast,
much less is known about the mechanics by which maternal depression impacts
specifically on a young child’s language development and the role of the
attachment process in this. One proposal is that maternal depression impacts
negatively on the attachment process which then leads to a reduction in the
amount of shared time a mother will interact with her child and ultimately
resulting in fewer opportunities for a child to develop their language skills
(Paulson et al, 2009). However, the literature is inconclusive about the impact
of parental depression. On the one hand Pan et al (2005) found that maternal
depression had a negative impact on the child’s rate of vocabulary growth
between the ages of one and three years in children of low income families. On
the other, Paulson et al (2009) found an association between both maternal and
paternal depression and the amount of parent-to-child reading that took place,
but only the father’s depression impacted on child’s language development
(expressive vocabulary) at 24 months.
Some of the literature around child neglect and
language development may be of relevance here, although it is acknowledged that
this literature is very specific to this group of children. The few studies in
this area to date suggest that severe parental neglect has more of an impact on
children’s language development than physical abuse (Culp et al, 1991; Allen
& Oliver, 1982; Eigsti & Cicchetti, 2004). Explanations for this
finding are weak but propose that children who are neglected are more likely to
stay in the home where language stimulation is poor whereas children who are
physically abused are usually removed from the parental home into a more
verbally stimulating environment.
`The relevance of these findings is in trying to understand
whether the impoverished language of children who are severely neglected is due
to specific factors related to the impoverished communication environment or
the more cumulative effects of social risk. Some insights have been offered
into this by a recent study that has identified specific risk factors rather
than cumulative effects of social risk. These specific risk factors are 1)
maternal depression; 2) the mother’s own history of neglect and/or abuse and 3)
the mother’s poor attachment to the child (Sylvestre & Merette, 2010).
Therefore,
there is some evidence to show that the mother’s capacity to provide a
communicative environment is certainly influenced by her mental well being and
the attachment she has with her child. However, much of this research needs
further confirmation in other cohorts. Of particular interest, is whether
mothers perceive they are supported in maintaining or increasing their capacity
to engage in and provide an adequate communication environment. To date, there
is very little research which explores these perceptions.
2.5 The Developmental Stages of
Children
2.5.1 Cognitive Development
Cognitive
development refers to the progressive and continuous growth of perception,
memory, imagination, conception, judgment, and reason; it is the intellectual
counterpart of one’s biological adaptation to the environment (Nicolosi,
Harryman, & Kresheck, 1989). Cognition also involves the mental activities
of comprehending information and the processes of acquiring, organizing,
remembering, and using knowledge (Owens, 2008). This knowledge is subsequently
used for problem solving and generalization to novel situations.
Many theories
have been proposed regarding how children learn about their environment and how
cognitive development proceeds. One of the significant theorists in this area,
Jean Piaget, viewed the child as an active participant in the learning process.
He considered that new learning took place as the child interacted with the
environment and with other people.
According
to Piaget, cognitive development is based primarily on four factors:
maturation, physical experience, social interaction, and a general progression
toward equilibrium (Piaget, 1954). Piaget’s theories have withstood the test of
time, and more recently have been considered in new light with regard to the
effort that a child makes in learning language. For example, Bloom and Tinker
(2001) have proposed a model for language development that suggests language
emerges out of complex developments in cognition, social–emotional development,
and motor skills. This model ties in nicely with what Piaget suggested more
than 50 years ago—namely, that the child learns by acting on the environment
(and with others). In other words, what begins as sensorimotor activity gradually transforms into complex, abstract thought.
For
Piaget, cognitive or intellectual development is the process of restructuring
knowledge. The process begins with a cognitive structure, or a particular way
of thinking. This way of thinking is based on what the child currently knows or
has experienced. As the child encounters a novel experience, disequilibrium is created. The child must compensate for
this disturbance and solve the conflict between what he currently knows and his
new experience. Piaget referred to this process as adaptation (Piaget,
1954). All organisms must adapt in response to changes in the environment, and
it is through this process of adaptation that a child integrates new
information.
Two aspects
of the adaptation process are key: assimilation and accommodation.
Assimilation refers to the child’s attempts to
incorporate new stimuli into existing cognitive schemas (structures). For
example, suppose a child is familiar with dogs because there is a German
shepherd at home, and then she encounters a poodle. The child is able to
assimilate the features of the poodle into the cognitive schema she has for dogs
because the poodle and the German shepherd share a number of core
features. Thus, as the child encounters varied breeds of dogs in her life, she
recognizes the common aspects that these animals share and incorporates the new
features into her cognitive schema for dogs . This strategy allows the child to
integrate and organize new information and assists in development of
categories. When a child encounters a new stimulus that does not fit into his
existing cognitive
schema, his
cognitive processes undergo the process of accommodation , whereby new schemes are
developed to integrate the new information. Thus, if a child encounters a
donkey for the first time, he may initially try to incorporate this new animal
into his cognitive schema for dogs . Of course, the donkey is a vastly
different type of animal and cannot be integrated into the dog schema, so a new schema is created. As each
of these adaptations in cognition is made, the child is continuing on his path
to maintain equilibrium with the environment.
Multiple
theories have been put forth regarding the process of cognitive development and
the relationships between cognition and language. It is clear that cognition,
at least initially, precedes language development, and many cognitive aspects
are prerequisites to language development. The relationship between cognition
and language likely grows more interdependent over time, as growth in one area
fuels growth in another area. Although Piaget’s theory of the stages of
cognitive development in young children did not answer all questions about
cognition in early childhood, his descriptions of cognitive achievements in
childhood can help us understand other aspects of the child’s behavior,
including the acquisition of milestones in language development.
In observing
children, Piaget noticed patterns in their responses to intellectual tasks.
Children of
similar ages responded in ways that were, at the same time, remarkably similar
and yet remarkably different from adult responses and expectations. Likewise,
children at different ages had their own characteristic way of responding
(Labinowicz, 1980).
The
first two stages of cognitive development, the sensorimotor and preoperational
periods, are collectively termed the preparatory, prelogical stages . Likewise,
the concrete and formal operational stages are collectively termed the advanced, logical thinking stages. Each individual stage, however, is
characterized by specific developmental milestones. Beginning at birth and
extending to age two years, the child coordinates his physical actions. This
stage is termed the sensorimotor period. The child’s behavior, while primarily
motoric, is described as preoperational and preverbal;
there is no conceptual thought, although
2.5.2
Motor Development
When we talk
about motor development, we usually consider gross motor and fine motor skills. Gross motor skills refers to movements involving large
muscles, such as trunk muscles used for sitting upright and leg muscles used
for walking. Smaller muscles, such as those in the fingers or tongue, are used
for fine motor tasks, such as writing or talking,
respectively. The professionals who are most often involved in the assessment
of motor skills in children include physical and occupational therapists. The
major motor development achievements of the first 18 months of life. For
example, the skill of walking can be expected to emerge anytime between 8
months of age and 18 months of age, with the median age expected to be 12
months. That is a wide window during which this skill may emerge. Thus a child
who is not walking at 14 months is not necessarily impaired in gross motor
development, although she should be evaluated carefully by an appropriately
trained specialist who could assess evidence of other skills involving gross
motor development. As can be seen from Figure 2-1, some gross motor skills
should emerge earlier in development, such as crawling, walking with assistance,
and then standing alone. If these skills are not yet present in a 14-month-old
child, there may be greater cause for concern.
2.5.3
Social Emotional Development
Social–emotional
development in children is most often evaluated by psychologists and teachers.
A child must be interested in socializing and communicating with others to be
an effective communicator. Consequently, difficulties with social interaction
can profoundly impair communication; indeed, this problem is one of the
hallmark features of autism (Gerber, 2003).
In
early infancy, we are most concerned with a child’s connectedness with his
world. This connectedness is initially expressed through nonverbal modes, such
as eye contact and facial expression. The infant will produce a behavior that
elicits a reaction in the environment. The infant will respond to this
reaction, thereby resulting in learning. For example, in the first month of
life, a baby will smile reflexively. There is no evidence that the smile is of
itself a planned action. In response, adults in the environment will usually
react in a positive manner, using exaggerated vocalizations and laughter. Over
time, the infant learns that the smile elicits a very positive reaction from
others. Thus, between two and seven months of age, we see the emergence of a
social smile, which is a purposeful act. Its development is evidence that
learning has taken place for this young child.
A
key behavior that is of interest to those who work with young children is the
ability to achieve and then maintain self-regulation. Development of regulatory
capacity evolves from control of physiological responses to control of
emotional state and attention (National Research Council & Institute of
Medicine, 2000)—in other words, the child’s ability to maintain homeostasis
, or to keep everything in balance. When infants are first born, they have
little regulatory capacity beyond keeping their physiological responses in balance,
such as body temperature, heart rate, and respiration. These behaviors are not
under the baby’s volitional control. Initially, responses to stimulation in the
environment are not under the baby’s control, but rather occur automatically,
leading them to be called reflexive responses. For example, an infant will
startle in response to a noise or will begin to suck in response to a touch on
the cheek. As the infant matures, these reflexes are integrated as the infant’s
ability to self-regulate (i.e., control the body) grows over time. The
ability to self-regulate is very helpful to the learning process and is related
to the adaptation process described by Piaget’s theory of cognitive
development.
All
humans are bombarded with sensory input almost constantly. Our bodies are
exposed to visual, auditory, tactile, and olfactory stimuli, as well as changes
in temperature, motion, and balance. We must make decisions about how and when
to respond to each of these stimuli.
As
we mature, we learn to ignore certain stimuli and to pay attention to others.
This ability to discriminate between stimuli, and then determine which to
ignore (or suppress) and which to attend to, is at the core of regulatory
development.
Sleep–wake
cycles are good examples of the development of regulation. In the first month
of life, infants sleep many hours per day. They awaken briefly to feed and then
fall asleep again for just a few hours. This pattern continues throughout the
day and night, and results in parents who are constantly tired. After the first
few weeks of life, the infant is able to maintain the awake state for a longer
period of time, which provides the baby with an opportunity to observe and
learn from her environment. The time during which the infant remains awake lengthens.
Although the
sleep periods lengthen, they decrease in number. This is an example of the
development of regulation for the sleep–wake cycle. The result is a rested,
alert baby and happy,rested parents! Now consider what happens when a baby is
not well or has symptoms of “colic” (where the baby cries for hours at a time):
Both baby and adult become dysregulated in this scenario and, as a result, are
less attentive to and appreciative of stimuli.
Infants
have a preference for faces, and it is through this preference that they
establish the foundation for early social relationships with others. Children
establish imitation skills by studying others in their environment. This
practice begins as imitation of facial expressions (such as smiles) and then
develops into imitation of more complex behaviors, such as actions on objects
(e.g., throwing a ball, emptying a container), specific motor patterns (e.g.,
clapping, dancing), and eventually speech and language development. A strong
social–emotional foundation is key to the development of verbal language
behaviour.
2.5.3
Linguistic Development
In
the first two months of life, infants make sounds for limited purposes. They
may cry to seek assistance, usually for fulfillment of a physical need such as
hunger or other discomfort. When they are calm and in a regulated state, they
may make pleasure sounds; these noises may sound like vowels, but are not yet
true speech sounds. Nevertheless, these quasi-resonant nuclei may form the basis for later sound-making.
As
the infant approaches three to four months of age, he produces cooing sounds,
which approximate a single syllable consisting of a consonant and a vowel. The
child’s production of different vowels also increases and diversifies. Sometime
after four months of age, the infant begins to babble, which consists of
production of strings of consonant–vowel productions.
Initially these
vocalizations will consist of repetitions of the same sound pattern over and
over (e.g., ba-ba-ba ). As time
goes on, the variety of sounds used in one string will vary, and the babble
becomes more complex (e.g., ba-ta-ba-taba-ti-ba-ti ). Intonation,
volume, and pitch begin to vary, too. As the infant approaches 9 to 10 months
of age, this vocal pattern is called jargon. At this time, adults will report
that the baby seems to be speaking a true language, except without true words.
The jargon is often accompanied by gestures and body movements, as well as
changes in facial expression. All of these developmental behaviors prepare the
child to eventually use true words, first by themselves, and then in strings of
longer and longer phrases. Sometime around 10 to 12 months of age, the first
word emerges. The first word is typically an approximation of the true word, in
that the child must produce a simplified version.
Another
development that will occur typically before the first birthday is imitation of
adult speech. This seems to be both a word-learning strategy and a social
bonding strategy for the child. Imitation serves many purposes for a young
child learning to communicate. For instance, it is a way for the child to
experiment with words, as adults will provide feedback to the child based on
how appropriate the child’s word choice was. It is also a way for the child to
engage in a “conversation” with the adult, without requiring the child to have
a large expressive vocabulary. Consider the following exchange between a
15-month-old child and her parent while walking in the park:
Parent:
Oh, look at the bird! (points to a bird pecking at the ground)
Child:
Ba. (gestures toward the bird)
Parent:
Oh, do you like the bird? Isn’t it pretty? I think it’s eating. Look at it eat!
Child:
A. (while looking at the bird)
Parent:
That’s right, it’s eating.
Parent:
Oh, it’s going bye-bye. (points to the bird and waves as it flies away)
Child:
Ba. (waves)
This
brief exchange is a rich example of conversation as a word-learning experience
and social opportunity for a young child. The child participates in an event
(watching a bird) while hearing a noun ( bird ), a descriptor (
pretty ), and action words ( eat, eating, going, bye-bye ). The
simultaneous exposure to an event linked with words provides an opportunity for
the child to learn the meanings of words, thereby building both comprehension
and vocabulary. Through use of imitation, the child is also able to participate
in a verbal exchange with the parent or caregiver, over several turns, while
using very few sounds or words.
Bloom and Tinker (2001) have proposed a
three-component model of language development, termed the intentionality model , which emphasizes
the impact of engagement (social and emotional development) and effort (cognitive development) in the process of
language acquisition. In this model, the child’s responsiveness to the environment,
and his social connectedness to others, establishes for the child what is
relevant to learn and what the motivation to learn is. The concept of cognitive
effort concerns the work that is required in actively learning about the world.
A child must be socially connected to the world and motivated to learn more
about the world to figure out how to communicate with others. Thus the
intentionality model brings together the components of cognition and
social–emotional development and unites them with language in a clear way
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