This document provides an overview of a student paper comparing language development in children to second language acquisition in adults. It discusses various theories of both language development and second language acquisition. The key conclusion is that while both are influenced by internal and external factors, the factors differ and are more supportive for language development in children. As adults, the external factors and need that support language development in children are not as strong, making second language acquisition more difficult.

1. Running Head: LANGUAGE DEVELOPMENT AND ACQUISITION
Children’s Language Development versus Adult Second Language Acquisition
Dylan Djani
Extended Essay Final Draft
Advisor: Mrs. Ford
TOK Teacher: Dr. Cliff
Date: December 14, 2009
Word Count: 3879
IB Candidate Number: 000503-006
1

2. Running Head: LANGUAGE DEVELOPMENT AND ACQUISITION
Contents Page
Abstract Page 3
Language Development and Second Language Acquisition Page 4
Introduction Page 4
Aspects of Language Page 5
Language Development Page 6
Theories of Language Development Page 7
Second Language Acquisition Page 10
Theories of Second Language Acquisition Page 12
Comparing Language Development and Second Language Acquisition Page 14
Conclusion Page 16
References Page 17
2

3. Running Head: LANGUAGE DEVELOPMENT AND ACQUISITION
Abstract
Being fluent in multiple languages is an extreme asset in today’s society, and the
requirement to be able to speak another language in the workplace is ever increasing. In order to
create an effective language acquisition method, language development as a child should be
compared to acquiring a second language as an adult for similarities and differences that might
aid researchers in creating a language learning method that works for a greater percentage of the
population. Thus, the research question is how does language development as a child compare to
second language acquisition as an adult? By researching language development and second
language acquisition and investigating multiple theories regarding both topics, an important
conclusion can be made: internal and external factors affect both language development and
language acquisition; however, the factors are different for both and also vary. The factors that
allow for language development are no longer there as an adult, making second language
learning as an adult much more difficult. A variety of theories support this, such as the
communication-pressure hypothesis, among others. An ideal language-learning method is one
that works for the most amount of people, and language researchers might be able to become
closer and closer to this goal by singling out the factors of language development that still exist
as an adult.
3

4. Running Head: LANGUAGE DEVELOPMENT AND ACQUISITION
Language Development and Second Language Acquisition
Introduction
Foreign languages play a role of ever-increasing importance in today’s society, as more
and more jobs require the ability to converse in languages other than English. As a result
language-learning methods are also becoming more and more important. Psycholinguistics is the
study of speech or language and how it is developed or acquired (Slobin, 1971). Many attempts
have been made using psycholinguistic research to create a program of language learning that
maximizes the learning and consequent performance in the language and minimizes the time
necessary to achieve proficiency, such as Pimsleur or Rosetta Stone. By analyzing the language
development of a child and the process of acquiring a second language as an adult for potential
similarities and differences, a better understanding of the most efficient method of obtaining
fluency in a second language. In other words, a further comprehension of the process of second
language acquisition can lead to improved methods of teaching a second language. Language
development and acquisition are used synonymously, and from some points of view this is
plausible, but in order to compare language development to second language acquisition, the
operational definition of the terms “development” and “acquisition” must be clarified.
“Language development” or “language acquisition” may be used interchangeably, but the term
“second language acquisition” will only be used to refer to the acquisition of a second language
as an adult. How does the development of language as a child compare to the acquisition of a
second language as an adult? Many theories regarding both language development and second
language acquisition have been postulated by various psychological schools of thought. The
underlying difference between the theories is whether or not language development and second
language acquisition are results of nature, or having a biological predisposition or programming
4

5. Running Head: LANGUAGE DEVELOPMENT AND ACQUISITION
specifically for that purpose, or nurture, one’s environment, or a combination of the two. Nativist
theories claim that both language development and second language acquisition are a result of
nature, whereas environmentalist theories maintain that they are a result of nurture. Research
regarding bilingualism is also relevant because it provides a basis for comparison for second
language acquisition performance. The development of language as a child has more of an
ease than the acquisition of a second language as an adult because external factors from the
environment and internal biological factors work together to allow for language
development as a child; as an adult external factors and internal factors play less of a role
in second language acquisition because the need to quickly learn a second language does
not arise often in everyday life.
Aspects of Language
The two main aspects of language are production and comprehension, of which the
corresponding brain parts are the Broca’s and Wernicke’s Areas respectively (Myers, 2003). At
the base of all languages are phonology, or how the language sounds; semantics, or the meanings
of words; and syntax, or the organization of words and phrases. Phonology can be broken down
into three levels: phonemes, morphemes, and semantics. Phonemes are individual speech sounds
in a language, and morphemes are the smallest unit of meaning in a language (Spencer, 1991).
Examples of phonemes are the sounds of the letters c, a, and t in the word “cat.” Examples of
morphemes are prefixes, suffixes, or stems, such as “pre”, indicating before, or “ed” indicating
the past. The semantics of a language in this case refer to the rules of a language regarding
sentence units and word order and the meaning of them. This differs from the semantics as listed
with phonology and syntax because the semantics under the heading of phonology account for
5

6. Running Head: LANGUAGE DEVELOPMENT AND ACQUISITION
the rules of a language, whereas the semantics at the base of all languages refer to the meanings
of words.
Language Development
Language development occurs in stages that research has shown to be constant for all
races and genders (Myers, 2003). The rate at which the language development occurs is,
however, different for each individual. The stages of language development are the babbling
stage, one-word stage, two-word stage or telegraphic speech, and the development of syntax
(Slobin, 1971). The babbling stage begins anywhere between six to twelve months of age and
consists of the baby uttering sounds that do not correspond to any particular language. The one
word stage occurs between twelve and eighteen months, where the child speaks using mostly
single words. Telegraphic speech normally occurs after eighteen months and consists of the child
speaking like a telegram without any auxiliary words, such as “could,” “would,” “ought,” or
“must.” Evidence of the child learning concepts about language can be seen in this stage. In the
final stage of language development, which begins between eighteen and twenty-four months,
the child develops proper syntax and a greater range of vocabulary. Grammatical development
begins in the two-word stage, but the child’s speech can begin to be characterized by hierarchical
structures once the child speaks phrases longer than two words, regardless if these phrases are
correct.
Overgeneralization of grammatical rules and negative evidence also plays a role in
language development (Farrar, 1992). As language development occurs, the child’s grammar
moves from being incorrect to more correct as morphemes such as “ed” are used correctly, but
overgeneralization of rules such as the use of “ed” also occur, with the result being the child’s
usage of words such as “goed” and “doed.” Negative evidence is provided to a child when a
6

7. Running Head: LANGUAGE DEVELOPMENT AND ACQUISITION
child’s grammar is corrected through expansions or recasts, although the exact role of negative
evidence is not certain (Morgan, Bonamo, Travis 1995). Expansions are the responding to a
child’s incorrect grammatical sentence with the grammatically corrected version of the child’s
statement (Shaffer, 1993). Recasts are responding to a child’s incorrect grammatical sentence
with a non-repetitive grammatically corrected statement. According to Farrar’s study children of
the average age of 22.8 months were more likely to use correct grammatical morphemes that
were heard in recasts than to use the same information heard outside of recasts, which suggests
that the negative evidence given by recasting a child’s grammar aids the child’s grammatical
development. On the other hand the study done by Morgan, Bonamo, and Travis shows
contradicting results: the analyses failed to show any relationship between recasts and later usage
of correct grammar or self-corrections, but the cumulative effects of recasts was shown to be
related to the child’s overall correct use of grammar. Morgan, Bonamo, and Travis’s possible
explanation for this is that the recasts have an alternative function, namely to encourage a variety
of usage of the language. Their study was a longitudinal study, which eliminates the confounding
variables that would arise if they had not used the same subjects repeatedly.
Theories of Language Development
Theories regarding language development come from a multitude of psychological
schools of thought (Shaffer, 1993). The learning perspective emphasizes processes such as
imitation and reinforcement, which shape the child’s language as the child progresses through
the stages of language development. The nativist perspective holds that humans have an innate,
biological predisposition or programming to develop language. The interactionist perspective
argues that both environmental influences and biological factors combined result of language
7

8. Running Head: LANGUAGE DEVELOPMENT AND ACQUISITION
development. The disagreement between language development being a result of nature or
nurture is clearly seen by the differences between the various theories.
Among the first learning perspective theories for language development was Skinner’s
theory that children learn to speak properly due to being reinforced to speak with proper
grammar (Shaffer, 1993). The parents do so by shaping the child’s language and by correctly
interpreting the message that the child is trying to convey. Roger Brown and Camille Hanlon
found that parents are more likely to correct the semantics of the child’s early speech as opposed
to the actual grammatical correctness, which shows that grammatical reinforcement alone cannot
be solely responsible for language development. According to the communication-pressure
hypothesis children learn to speak more grammatically correct due to the need to communicate
effectively to express other needs. This is supported by multiple studies, such as Hoff-Ginsberg
(1996) and Norman-Jackson (1982), of which the results showed that children’s language
development is affected by the willingness of the parents (or other close figures) to initiate and
maintain conversations with the child, but not necessarily reinforcing grammatical correctness. A
social learning theory for language development argues tat language development is a result of
operant conditioning and imitation (Myers, 2003). Studies such as Rice and Wodsmall (1988)
have shown that children quickly learn the meaning of many words in a short period of time, and
children who grow up in specific regions of the world develop regional accents. This shows that
imitation is an important factor for language development.
The nativist perspective argues that language development is a result of biological
processes, and a major proponent of this is Noam Chomsky (Myers, 2003). He postulated that
humans are born with a language acquisition device (LAD), which is an inborn model of the
structure of human languages and the child only needs to acquire enough vocabulary to be able
8

9. Running Head: LANGUAGE DEVELOPMENT AND ACQUISITION
to learn a language. Another nativist, Dan Slobin, disagreed with Chomsky about the LAD,
instead arguing that humans have an inborn language-making capacity (LMC), which is a set of
specialized cognitive and perceptual abilities for language learning (Shaffer, 1993). Evidence for
the nativist perspective includes studies that have shown that chimpanzees are capable of
producing American Sign Language words, but with no command of appropriate syntax that is
clearly different from a child in the telegraphic speech phase of language development. Nativists
argue that this is because only humans are born with an LAD or LMC. Eric Lennenberg is
another nativist who strongly stands behind the critical-period hypothesis, which states that
human beings are most equipped to learn language before they reach puberty. A major critique of
the nativist approach is that it does not actually explain language development, which renders it
incomplete.
The interactionist perspective argues that both biological and environmental, or internal
and external, factors combined are responsible for language development (Shaffer, 1993). The
interactionist Piaget argued that language development reflects the child’s cognitive
development, and all children go through the same stages of language development because they
go through the same stages of intellectual growth. Other interactionists agree that cognitive
development plays an important role in language development, but do not place as much
emphasis on it as Piaget. The interactionist perspective accounts for many observations, such as
the observation that children hardly ever produce hypothetical statements until around the age of
four or five. This is because children under this range of ages do not have the capacity to think
about possibilities as opposed to what is actually going on and do not have the ability to change
the frame of reference in their minds to the past or future to make hypothetical statements. Like
the nativists, the interactionist approach argues that children are predisposed to learning
9

10. Running Head: LANGUAGE DEVELOPMENT AND ACQUISITION
language, but place emphasis on cognitive development and social factors, which result in
language development.
Second Language Acquisition
The stages of second language acquisition are not as concrete as those of language
development, and many other factors must be considered when analyzing second language
acquisition. A general set of stages for second language acquisition, which is used by Saville-
Troike to compare second language acquisition to language development, is the flow from an
initial state regarding knowledge of the language to intermediate states and eventually to a final
state (Saville-Troike, 2006). For acquiring a second language as an adult the initial state involves
knowledge of a first language, including how language works. This knowledge of a first
language is necessary for the transfer from the first language to the second language. Other
aspects of this initial state include world knowledge and skills required for interaction, as both
are necessary to learn a second language. Intermediate states vary and involve the transfer of
prior knowledge. Two main types of transfer are positive transfer and negative transfer, or
interference. Positive transfer occurs when a structure or rule of the initial language is used in the
second language, and that use in the second language is correct. Negative transfer occurs when a
structure or rule of the initial language is used in the second language, but that specific use is
incorrect. A necessary condition for a person to progress through intermediate states is language
input, although the input does not have to be reciprocal. Facilitating conditions are feedback,
aptitude, motivation, and instruction. These are not required to progress through intermediate
stages, but aid the progression. The final state is a high level or near native-like competence in
the second language; however, adults who acquire a second language can never reach total native
linguistic competence because the definition of native linguistic competence entails
10

11. Running Head: LANGUAGE DEVELOPMENT AND ACQUISITION
simultaneous multilingualism. A major factor affecting second language acquisition is age. If a
child hears and responds in multiple languages before around the age of three, then the child will
develop simultaneous multilingualism, or have two “first languages.” Other studies have shown
that, once past the age of twelve or thirteen, learning a second language becomes more difficult.
The other type of multilingualism is sequential multilingualism, which refers to acquiring the
second language after the first language. Sequential multilingualism is the ideal goal for adults
who wish to acquire a second language. Other factors that influence second language acquisition
must be taken into consideration, such as individual, external, and internal factors (Moyer, 2004).
Schumann came up with a list of individual factors that influence second language acquisition,
the headings of which were neurological factors, personality factors, cognitive factors,
instruction/input factors, and social factors. Among these factors include subtopics such as brain
lateralization, motivation, intelligence, methods of teaching, et cetera. Differences in the process
of and time required to reach proficiency in a second language acquisition are attributed to these
factors, as the factors clearly vary from person to person. (Sanz, 2005).
Going further with multilingualism, Weinreich also identified types of bilingualism in
1953 (Vetter, 1969). In the first type of bilingualism each language is treated as a separate
system, and each word has its own separate significance and meaning within each language. In
the second type of bilingualism words from both languages have the same significance. This type
is called coordinate bilingualism. The third type of bilingualism is where the speaker learns the
second language by means of the first language and is referred to as compound bilingualism. An
example of the different types of bilingualism can be shown through the words “casa”, which is
Spanish for “house”, and the English word “house.” In the first type of bilingualism the
connection is not made between the words casa and house, and they are treated as separate
11

12. Running Head: LANGUAGE DEVELOPMENT AND ACQUISITION
entities. In the second type of bilingualism the word casa and the word house call to mind a
similar picture, and in the third type of bilingualism the speaker associates casa with the word
house, assuming the speaker is natively English and is learning Spanish. Coordinate bilingualism
parallels simultaneous multilingualism, and compound bilingualism parallels sequential
multilingualism. With this in mind, the same factors that determine whether a person develops
simultaneous or sequential multilingualism also determine whether the person has coordinate or
compound bilingualism. Moreover, adults with the goal of acquiring a second language have a
better chance of success with compound bilingualism as the goal.
Theories of Second Language Acquisition
Theories about second language acquisition come from different schools of thought, as
do the theories of language development (Saville-Troike, 2006). Nativist theories, such as Noam
Chomsky’s universal grammar or Krashen’s Monitor Theory, assert that humans are predisposed
to acquiring language, as well as developing it (Larsen-Freeman, Long, 1991). Other theories
involve neurocognitive approaches such as the Declarative/Procedural Model.
The nativist perspective has a similar approach to second language acquisition as to
language development in that both are believed to be a result of humans being biologically
programmed to learn language. Two major nativist theories of second language acquisition were
put forth by Noam Chomsky and by Stephen Krashen (Saville-Troike, 2006). Noam Chomsky’s
argues that all human languages have a common characteristic: Universal Grammar. Humans
possess an innate knowledge called the language faculty, which contains Universal Grammar and
allows children to acquire a second language by building upon the first language. A major goal
of Universal Grammar proponents was to determine whether or not the utilization of the
language faculty is available to adults learning a second language. Universal Grammar is
12

13. Running Head: LANGUAGE DEVELOPMENT AND ACQUISITION
conceptualized as a set of principles that are common to all human languages. Some principles of
Universal Grammar have parameters, where the grammar is limited in certain situations based on
the language being spoken. Universal Grammar guides children in language development, and
the beginning stages of second language acquisition involve using parameters for the first
language in the second language, as guided by Universal Grammar. This, however, often leads to
mistakes. As a result vocabulary acquisition is required to reset the parameters in Universal
Grammar so that they are in accordance with the new language. Krashen’s theory of second
language acquisition is called the Monitor Model and incorporates Chomsky’s LAD. The model
consists of five hypotheses about second language acquisition: acquisition-learning hypothesis,
monitor hypothesis, natural order hypothesis, input hypothesis, and affective filter hypothesis.
The first hypothesis states that the difference between acquisition and learning is that acquisition
is subconscious and involves the LAD, and learning is conscious and is used in classrooms to
learn a second language. The second hypothesis states that what is learned can only be used as a
monitor for editing what has already been produced. The third hypothesis says that humans
acquire rules of language in a predictable order. The fourth hypothesis states that language
acquisition occurs because there is comprehensible input, and if the input is understood, the
required grammar naturally follows. The last hypothesis states that input may not be processed if
there is an affective filter up, such as conscious learning. This theory had an impact on language
teaching by changing the way second languages were taught in the past, but failed to answer key
questions of second language acquisition.
A main cognitive neuroscience theory on second language acquisition is the
Declarative/Procedural Model. Lexicon and grammar are two main parts to the theory: lexicon
refers to information that must me memorized, such as all simple words and word-specific
13

14. Running Head: LANGUAGE DEVELOPMENT AND ACQUISITION
information, and grammar refers to the regularities of language. The main premise of this model
is that differences between lexicon and grammar are tied to the difference between the
declarative and procedural memory systems. The declarative memory system is tied to the
mental lexicon, and the procedural memory system is tied to the mental grammar. Regarding
second language acquisition as an adult, the expectation is that the acquisition of grammar with
procedural memory will be more problematic due to a variety of factors, such as a reduced
procedural memory due to a somewhat enhanced declarative memory that comes with age.
Basically a tendency to rely on the declarative memory system to memorize certain things that
should be done with procedural learning occurs, but as a speaker reaches higher levels of ability
in the second language, practice leads to procedural learning and an acquisition of grammar.
Comparing Language Development and Second Language Acquisition
Both language development and second language acquisition theories have in common
the typical nature versus nurture arguments; however, neither the nature nor the nurture argument
seems to be held in higher regard or as a correct and satisfying explanation. Taking each
perspective into account, both language development as a child and second language acquisition
as an adult require the interplay of external and internal factors. However, the interplay of factors
that trigger language development as a child seem to fall into place accordingly, independent of
individual factors and situations. On the other hand the interplay of factors connected to second
language acquisition include individual factors, which account for differences in ability in the
second language over time. This makes sense when considering the communication-pressure
hypothesis because once a child can effectively communicate in one language the need to be able
to express his or her needs is met, which would logically cause at least some of the factors
allowing for the rapid learning of a language to cease to exist due to lack of importance. If both
14

15. Running Head: LANGUAGE DEVELOPMENT AND ACQUISITION
biological and environmental factors are responsible for language development, as suggested by
the various theories for both language development and acquisition, then the possibility also
exists that some of the unimportant factors are biological or internal, which would mean that the
brain stops viewing the need to gain language as necessary, which would contribute to the
difficulty of acquiring a second language later on in life. This coincides with the individual factor
of age in second language acquisition and how the difficulty of learning a second language
increases after a certain critical window. This also helps explain why stages of language
acquisition have been shown not to be as orderly and common across cultures as the stages of
language development. The declarative/procedural model of second language acquisition
supports how age is a very important factor that separates language development from second
language acquisition by postulating that reliance on declarative memory comes with age.
Interactionist theories come the closest to covering the wide breadth of results of various studies
in that they acknowledge external and internal factors of language development; however, this
should be extended to second language acquisition. Individual factors play more of a role in
second language acquisition than in language development, which is a possible contributing
factor to the differences in the stages. In other words, the interaction of external and internal
factors that allow for children to develop language does not occur for adults because a certain
amount of the factors are no longer there, which causes a rise in difficulty for second language
learners as adults and prompts language researchers to find solutions!
15

16. Running Head: LANGUAGE DEVELOPMENT AND ACQUISITION
Conclusion
As described by the various nature versus nurture and miscellaneous theories regarding
language development and second language acquisition, a variety of factors account for both
language development and acquisition, albeit different factors for each. Examples of factors that
affect language acquisition, but not development, are age and motivation. Factors that affect
language development, but not acquisition, are not a far-fetched idea due to the way children
quickly develop language. As per the communication-pressure hypothesis, children develop
language out of a need to communicate, and as adults this need is already met, and so the
pressure no longer exists, which eliminates specific factors relevant to language development.
Interactionist theories for language development support the idea of a variety of external and
internal factors causing language development, which is the most logical idea due to the vast
amount of results of studies that cannot be explained through a strictly nature or nurture theory.
By extending and incorporating ideas from other second language acquisition theories, an
interactionist theory explaining second language acquisition and its intricacies might be able to
aid language researchers in creating an effective language acquisition method. Furthermore,
singling out the factors of language development that still exist as adults may provide a key to
unlocking future language learning methods. Advancements in language learning methods have
already been attempted through programs such as Rosetta Stone and Pimsleur; however, neither
method works for every individual.
16

17. Running Head: LANGUAGE DEVELOPMENT AND ACQUISITION
References
Farrar, M. J. (1992). Negative evidence and grammatical morpheme acquisition. Developmental
Psychology, 28(1), 90-98.
Larsen-Freeman, D., & Long, M. H. (1991). An introduction to second language acquisition
research. Malaysia: Longman Group UK Limited.
Morgan, J. L., Bonamo, K. M., & Travis, L. L. (1995). Negative evidence on negative evidence.
Developmental Psychology, 31(2), 180-197.
Moyer, A (2004). Age, accent, and experience in second language acquisition. Great Britain:
Cromwell Press Limited.
Myers, D. G. (2003). Psychology. New York, NY: Worth Publishers.
Sanz, C. (Ed.). (2005). Mind and context in adult second language acquisition: methods, theory,
and practice. Washington, DC: Georgetown University Press.
Saville-Troike, M. (2006). Introducing second language acquisition. United Kingdom:
Cambridge University Press.
Shaffer, D. R. (1993). Developmental psychology: children and adolescence. Belmont, CA:
Wadsworth Inc.
Slobin, D. I. (1971). Psycholinguistics. Glenview, IL: Scott Foresman and Company.
Spencer, A. (1991). Morphological theory. Malden, MA: Blackwell Publishers Limited.
Ullman, M. (2005). A cognitive neuroscience perspective on second language acquisition: the
declarative/procedural model. In C. Sanz (Ed.), Mind and context in adult second
language acquisition: methods, theory, and practice (pp. 141-178). Washington, DC:
Georgetown University Press.
17

18. Running Head: LANGUAGE DEVELOPMENT AND ACQUISITION
Vetter, H. J. (1969). Language behavior and communication: an introduction. Itaska, IL: F.E.
Peacock Publishers, Inc.
18