Theories of Second Language Acquisition

THE THEORIES OF SECOND LANGUAGE ACQUISITION

THE PRINCIPAL purpose of this book is to offer teachers and future teachers information for developing an integrated understanding of the principle of second language acquisition (SLA) that underlie the pedagogical process. That purpose has necessarily involved theoretical consideration. A theory, as I note in the first chapter, is an extended definition.

            Is there such an integrated, unified theory of SLA, a standard set of constructs to which large numbers of researchers and teacher predominantly subscribe? The answer is, not exactly. As surely as competing models are typical of all disciplines that attempt to give explanatory power to complex phenomena, so this field has its fair share of claims and hypotheses, each vying for credibility and validity.

            In this chapter we will critically examine a number of current generalizations, hypotheses, and models of SLA. Remember that such “opinion” about SLA may represent one view of that metaphorical mountain of factors we talked about in chapter 1. Form such varied perspectives we should be able to place a large number of variables (which have been defined and discussed in this book) into a reasonable consistent tapestry of factors. That self-constructed system of variables is one’s theory of SLA.

BUILDING A THEORY OF SLA

To say that second language learning is a complex process is obviously trite. The pages of this book alone bear testimony to that complexity. But complexity means that there are so many separate but interrelated factors within one intricate entity that is exceedingly difficult to bring order and simplicity to that “chaos” (Larsen-Freeman 1997). We must nevertheless pursue the task of theory building (Long 1990a; Spolsky 1996). Consider, for a few moments, some of the domains and generalizations that describe the skeletal structure of a theory.

Domains and Generalizations

First, take a look at a taxonomy that was proposed several decade ago (Yorio 1976), represented in Figure 10.1. this list of factor begins to give you an idea of the many different domains of inquiry that must be included in theory of SLA.

Certain factors subsumed in the chapter topics of this book are also a set of domains of consideration in a theory of SLA:

1.      A theory of SLA includes an understanding, in general, of what language is, what learning is, and for classroom contexts, what teaching is.

2.      Knowledge of children’s learning of their first language provides essential insights to an understanding of ALA.

3.      However, a number of important differences between adult and child learning and between first an second language acquisition must be carefully accounted for.

4.      Second language learning is a part of and adheres to general principles of human learning and intelligence.

5.      There is tremendous variation across learners in cognitive style and within a learner in strategy choice.

6.      Personality, the way people view themselves and reveal themselves in communication, will affect both the quantity and quality of second language learning.

7.      Learning a second culture is often intricately intertwined with learning a second language.

8.      The linguistic contests between the native and target language form one source of difficulty in learning a second language.

9.      Communicative competence, with all of its subcategories, is the ultimate goal of learners a they deal with function, discourse, register, and nonverbal aspect of human interaction and linguistic negotiation.

However general those nine statements are, they, along, with taxonomies such as Yorio’s, constitute a framework for a theory of SLA. That framework has had substance built into it in the course of each chapter of this book. The interrelationships within that framework have been dealt with. Determining the source of a second language learner’s error inevitably involves consideration of cognitive strategies and styles, group dynamics, and even the validity of datagathering procedures. No single component of this “theory” is sufficient alone the interaction and interdependence of the other components ate necessary.

Hypotheses and Claims

A theory of SLA is really an interrelated set of hypotheses and/or claims about how people become proficient in a second language. In a summary of research findings on SLA, Lightbown (1985: 176-180) made the following claims:

1.      Adult and adolescents can “acquire” a second language.

2.      The learner creates a systematic interlanguage that is often characterized by the same systematic errors as [those of] the child learning the same language as the first language, as well as others that appear to be based on the learner’s own native language.

3.      There are predictable sequences in acquisition so that certain structures have to be acquired before other can be integrated.

4.      Practice does not ma perfect.

5.      Knowing a language rule does not mean one will be able to use it in communicative interaction.

6.      Isolated explicit error correction is usually ineffective in changing language behavior.

7.      For most adult learners, acquisition stops- “ fossilizes “- before the learner as achieved nativelike mastery of the  target Language.

8.      One cannot achieve nativelike( or near- nativelike ) command of a second language in one hour a day.

9.      The learner’s task is enormous because language is enormously complex.

10.  A learner’s ability to understand language in a meaningful context exceeds his or her ability to comprehend Decontextualized language and to produce language of comparable complexity and accuracy.

A similar set of statements was made by lightbown and spada( 1993 ) outlining some myths about SLA-what one should not conclude to be necessarily a correct generalization. following are some of those “ popular ideas” that may not be supported by research (Ligtbown&spada 1993:111-116):

1. languages are learned mainly through imitation.
2. parents usually correct young children when they make errors.
3. people with high IQs are good language learners.
4. the earlier a second language is introduced in school programs the greater the likelihood of success in learning.
5. most of the mistakes that second language learners make are due to interference from their first language.
6. learners errors should be corrected as soon as they are made in order to prevent the information of bad habits.

Unlike Yorio’s (1976) list and the nine items that synopsized the chapter topics of this book, most of lightbown’s generalizations and myths do more than define a domain. They hypothesize directionality within a domain, and are therefore the subject of debate. Item 6 In first (lightbown 1985) list, for example, stems from studies that fail to show that eplicit error correction cause a permanent change in language production.

Criteria for a viable theory

How do we know if we have the appropriate components of theory of SLA? One answer to this question may lie in an examination chaos/complexity theory. The pathway that one learner takes in order to achieve success is different, and sometimes markedly so, from another’s.

Larsen-freemen (1997) suggested several lesson from chaos theory that can help us to design a theory of SLA. I have synthesized her comments below.

1. beware of false dichotomies. Look for complementarity, inclusiveness, and interface we have examined a number of continue in this book; it is important to see them just as that, and not as dichotomies.
2. beware of liner, causal approaches to theorizing. The “ butterfly effect” in chaos theory reminds us that the fluttering wing of a butterfly in the Amazonian forest can have a chain of reactions and interreactions that extend all the way to the path of a hurricane in Hawaii.
3. beware of overgeneralization. Pay attention to details. the smallest, apparently most insignificant of factors in learning a second language may turn out to be important! But on the other hand.
4. beware of reductionist thinking. It is every temping, with any chaotic, complex system, to oversimplify by taking some little part of the whole and extracting It from the whole system.

Michael long (1990a: 659-660)also tackled the problem of theory building in a umber of suggestions about “the least” a theory of SLA needs to explain. He offered eight criteria for a comprehensive theory of SLA :

1. Account for universals.
2. Account for environmental factors.
3. Account for variability in age, acquisition rate, and proficiency level
4. Explain both cognitive and affective factors.
5. Account for from-focused learning, not just subconscious acquisition.
6. Account for other variables beside exposure and input.
7. Account for cognitive/innate factors which explain interlanguagesystematicity.
8. Recognize that acquisition is not a steady accumulation of generalizations.

The process of theory building may be best illustrated in the form of several models of SLA tat have appeared in recent history. These correspond to the schools of thought introduced I chapter I and reintroduced throughout the book. While there is no viable behavioristic model of SLA (it would be far too limiting); we can identify a major innatist model, two cognitive models, and a social costructivist theory.

An Innatist Model

Krashen’s Five Hypotheses for Second Language Acquisition

One of the most contorversial theoretical perspectives in SLA in the last quarter of the twentieth century was offered by Stephen Krashen (1977, 1981, 1982, 1985, 1993, 1997) in a host of articles and books. Krashen’s hypotheses have had a number of different names. In the earlier years the “Monitor model” and the “Acquisition-Learning Hypothesis” were more popular terms; in recent years the “Input Hypothesis” has come to identify what is really a set of five interrelated hypotheses. These five hypotheses are summarized below.

1.       The Acquisition-Learning Hypothesis claims that adults second language learners have two independent ways of developing language ability:

n  Language Acquisition is a subconscious and intuitive process of constructing the system of a language, not unlike the process used by a child to “pick up” a language. It occurs very naturally in a non-threatening environment. However, the research strongly supports the view that both children and adults can subconsciously acquire languages.

n  Language Learning is conscious learning process in which learners attend what occurs at school in an academic setting. It is a conscious learning process in which learners attend to form, figure out rules and are generally aware of their own process. When we talk about rules and grammar of language, we are usually talking about learning.

According to Krashen, “fluency in second language performance is due to what we have acquired, not what we have learned.” (1981a:99). Adults should therefore, do as much acquiring as possible in order to achieve communicative fluency; otherwise, they will get bogged down in rule learning and too much conscious attention to the forms of language and to watching their own progress.

2.      The Monitor Hypothesis attempts to explain how acquisition and learning are used. Language is normally produced using our acquired linguistic competence. Conscious learning has only one function…as the “Monitor” or “Editor.” After we produce some language using the acquired system, we sometimes inspect it and use our learned system to correct errors. This can happen internally before we actually speak or write, or as a self-correction after we produce the utterance or written text.

3.       The Natural Order Hypothesis claims that we acquire parts of a language in a predictable order. Some grammatical items tend to come earlier in the acquisition than others. For example, the –ing progressive is acquired  fairly early in first language acquisition, while third person singular –s is  acquired later.

4.      Comprehensible Input Hypothesis claims that an important “condition for language acquisition to occur is that the acquirer understand (via hearing or reading) input language that contains structure ‘a bit beyond’ his or her current level of competence........If an acquirer is at stage or level i, the input he or she understands should contain i + 1” (Krashen 1981: 100). In other words, the language that learners are exposed to should be just far enough beyond their current competence that they can understand most of it but still be challenged to make progress. The corollary to this is that input should neither be so far beyond their reach that they are overwhelmed (this might be, say, i + 2), nor so close to their current stage that they are not challenged at all (i + 0).

5.      The Affective Filter Hypothesis claims that the best acquisition will occur in environments where anxiety is low and defensiveness absent, or, in Krashen’s terms, in contexts where the “affective filter” is low. The affective variables do not impact language acquisition directly, but can prevent input from reaching what Chomsky called the Language Acquisition Device. The LAD is the part of the brain that is responsible for language acquisition.

However, it is unfortunate that SLA is not as simply defined as Krashen would claim, and therfore his assumptions have been hotly disputed by some linguists, such as de Bot, Swain & Lapkin, Brumfit, White, Gregg, Mc. Laughlin, to name but few.

Second language learning clearly is a process in which varying degrees of learning and of acquisition can both be beneficial, depending upon the learner’s own styles and strategies.

Krashen’s Input Hypothesis’ difficulty is found in his explicit claim (1986: 62) that “comprehensible input is the only causative variable in second language acquisition.” In other words, success in foreign language can be attributed to input alone. Moreover, it is important to distinguish input  and intake. The latter is the subset of all input that actually gets assigned to our long-term memory store. Just imagine, for example, reading a book, listening to a conversation, or watching a movie – in any language. This is your input. But your intake is what you take with you over period of time and can later remember.

Seliger (1983) offered a much broader conceptualization of the role of input that gives learners more credits (and blame) for eventual success. Certain learners are what he called High Input Generators (HIGs), people who are good at initiating and sustaining interaction, or “generating” input from teachers, fellow learners, and others. Low Input Generators (LIGs) are more passive learners who do little endeavour to get input directed toward them. In two studies of second language learners, Seliger found that “learners who maintained high levels of interaction (HIGs) in the second language, both in the classroom and outside, progressed at a faster rate than learners who interacted little (LIGs) in the classroom” (p. 262)

 While  Krashen staunchly maintained that in the language classroom, “output is too scarce to make any important impact on language development.”, Swain and Lapkin offered convincing evidence that their Output Hypothesis was at least as significant as input, if not more so, in explaining learner success. In a review of the Output Hypothesis, de Bot (1996:529) argued that “output serves an important role in second language acquisition....because it generates highly specific input the cognitive system needs to build up a coherent set of knowledge.

A Cognitive Model

Cognitivist Theory views human beings as having the innate capacity to develop logical thinking. This school of thought was influenced by Jean Piaget’s work where he suggests that logical thinking is the underlying factor for both linguistic and non-linguistic development.

-            The process of association has been used to describe the means by which the child learns to relate what is said to particular objects or events in the environment. The bridge by which certain associations are made is meaning. The extent and accuracy of the associations made are said to change in time as the child matures.

-            Cognitivists say that the conditions for learning language are the same conditions that are necessary for any kind of learning. The environment provides the material that the child can work on.

-            Cognitivists view the role of feedback in the learning process as important for affective reasons, but non-influential in terms of modifying or altering the sequence of development.

Language Learning as a Cognitive Process

1. Learning a language involves internal representations that regulate and guide performance.
2. Automatic processing activates certain nodes in memory when appropriate input is present. Activation is a learned response.
3. Memory is a large collection of nodes.
4. Controlled processing is not a learned response. It is a temporary activation of nodes in a sequence.
5. Skills are learned and routinized only after the earlier use of controlled processes have been used.
6. Learner strategies contain both declarative knowledge i.e. knowing the ‘what’ of the language-internalized rules and memorized chunks of language, and procedural knowledge i.e. know the ‘how’ of the language system to employ strategies.

Mc Laughlin’s Attention-processing model

A more sound heuristic for conceptualizing the language acquisition process, one that did indeed avoid any direct appeal to a consciousness continuum, was proposed by Barry Mclaughlin and his colleagues  (McLaughlin 1978; McLaughlin 1987,1990b).  Their model juxtaposes processing mechanisms ( controlled and automatic ) and categories of attention to form four cells.

Controlled process are “capacity limited and temporary”, and Automatic processes are a relatively permanent” (Mclaughlin et al. 1983:142). The automatizing of this multiplicity of data is accomplished by a process of restructuring (Mcleod & Mclaughlin 1986; Mclaughlin 1987,1990b) in which  ” the components of a task are coordinated, intregated or reorganized into new units,  thereby allowing the ... old components to be replaced by a more efficient procedure” (Mclaughlin 1990b: 118).

Both ends of this continuum of processing can occur with either focal or peripheral attention to the task at hand; that is, focusing attention either centrally or simply on the periphery.  It is easy to fall into the temptation of thinking of focal attention as “conscious” attention, but such a pit fall must be avoided.  Both focal and peripheral attention to some task, may be quite conscious (Hulstijn 1990).

While many controlled processes are focal, some, like child first language learning of the learning of skills without any instruction, can be peripheral. Similarly, many automatic processes are peripheral, but some can be focal, as in the cast of an accomplished pianist performing in a concert or an experienced driver paying particular attention to the road on a foggy night. It is very important to note that in virtually every act of performing something, focal and peripheral attention actually occur simultaneously. McLaughlin (1990a) noted that the literature in experimental psychology indicates that there is no long-term learning (of new material) without awareness, an observation well documented by Loew (1997) and Schmidt (1990)  for second language learning in particular. A cognitive perspective of SLA entirely obviates the need to distinguish conscious and subconscious processing.

If, for example, peripheral attention is given to language forms in a more advanced language classroom, focal attention is no doubt being given to meaning, function, purpose, or person.

Implicit and explicit models

Another set of constructs for conceptualizing the varied processes of second language learning is found in models that make a distinction between explicit and implicit linguistic knowledge. In the explicit category are the facts that a person knows about language and the ability to articulate those facts in some way. Explicit processing differs from McLaughlin’s focal attention in that explicit signals one’s knowledge about language. Implicit knowledge is information that is automatically and spontaneously used in language tasks. Children implicity learn phonological, syntactic, semantic, and pragmatic rules for language, but do not have access to an explanation, explicitly, of those rules. Impliicit processes enable a learner to perform language but not necessarily to cite rules governing the performance.

Bialystok later (1982:183) equated implicit and explicit with the synonymous terms unanalyzed and analyzed knowledge: “unanalyzed knowledge is the general form in which we know most things without being aware of the structure of that knowledge”; on the other hand, learners are overtly aware of the structure of analyzed knowledge.

These same models feature a distinction between automatic and non-automatic processing, building on McLaughlin’s conception of automaticity.  Automaticity refers to the learner’s relative access to the knowledge. Knowledge that can be retrieved easily and quickly is automatic. Knowledge that takes time and effort to retrieve is non-automatic.  As was true for the Mclaughlin model, both forms of attention can be either analyzed or unanalyzed. An important dimension of this distinction is time. Processing time is a significant factor in second language performance, one that has pedagogical salience in the classroom. The length of time that a learners takes before oral production performance, for example, can be indicative of the perceived complexity of certain language forms in a task.

A SOCIAL CONSTRUCTIVIST MODEL: LONG’S INTERACTION HYPOTHESIS

One of the most widely discussed social constructivist positions in the field originally emerged from the work of Michael Long (1996, 1985). Taking up where, in a sense, Krashen left off, Long posits, in what has come to be called the interaction hypothesis, that comprehensible input is the result of modified interaction. The latter is defined as the various modifications that native speakers and other interlocutors create in order to render their input comprehensible to learners.

In Long’s view, interaction and input are two major players in the process of acquisition, a combination emphasized by Gass (2003). In a radical departure from an old paradigm in which second language classrooms might have been seen as contexts for “practicing” grammatical structures and other language forms, conversation and other interactive communication are, according to Long, the basis for the development of linguistic rules. While Gass and Varonis (1994) ably pointed out that such a view is not subscribed to by all, nevertheless a number of studies have supported the link between interaction and acquisition (Swain & Lapkin, 1998; Gass, Mackey, & Pica, 1998; van Lier, 1996; Jordens, 1996; Loschky, 1994; Gass & Varonis, 1994; Pica, 1987).

The other side of the story is that Long’s Interaction Hypothesis has pushed pedagogical research on SLA into a new frontier. It centers us on the language classroom not just as a place where learners of varying abilities and styles and backgrounds mingle, but as a place where the contexts for interaction are carefully designed. It focuses materials and curriculum developers on creating the optimal environments and tasks for input and interaction such that the learner will be stimulated to create his or her own learner language in a socially constructed process.  Further, it reminds us that the many variables at work in an interactive classroom should prime teachers to expect the unexpected and to anticipate the novel creations of learners engaged in the process of discovery.

FROM THEORY TO PRACTICE

There is relationship between theory and practice.  Theories are constructed by professors and researchers, who hypothesize, describe, measure, and conclude things about learners and learning and the teachers. And who are the practitioners of the theory? Practitioners are thought of as teachers who are out there in classroom everyday stimulating, encouraging, observing and assessing real-live learners.

According to Brown (2000), there are theories and models of SLA based on some theorists. There are Innatist, cognitive, and constructivist.

These are Theories and Models of SLA:

Innatist	Cognitive	Constructivist
[Krasen] ·        Subconscious acquisition superior to “learning” and “monitoring” ·        Comprehensible input {i+1} ·        Low affective filter. ·        Natural order of acquisition. ·        “Zero option” for grammar instruction.	[McLaughlin/Bialystok] ·        Controlled/ automatic processing (McL) ·        Focal/peripheral attention. (McL) ·        Restructuring (McL) ·        Implicit vs explicit (B) ·        Unanalyzed vs Analyzed (B) ·        Form focused instruction.	[Long] ·        interaction hypothesis ·        Intake through social interaction. ·        Output hypothesis (Swain) ·        HIGs (Seliger) ·        Authenticity ·        Task-based instruction.

The first model is Innatist showed that Language Acquisition Device (LAD) or Universal Grammar (UG) endowed to human being at birth. The Innatist theory is mainly concerned with first language acquisition. It asserts that human have access to the knowledge that is processed innately. One of its main pioneers is Naom Chomsky. Another theory came from Stephen Krashen. There are five hypothesis that proposed by Krashen in Innatist Model; that is Monitor Theory (MT). The second model is cognitive.  Cognitive model claims that learning language is the same with learning any other knowledge. As learning a new language is learning new information, learners logically go through controlled process first. The most outstanding research in SLA in this line shows that attention has an effect, while time pressure does not; extra time helps both those who know the rules of grammars explicitly and those who do not. In conclusion, cognitive theories believe that human being employs their mind to learn all things, including language, in the same manner; speech-production is a matter of information processing process. And the last model is constructivist. In constructivist model, the interpersonal context is focus of observation and explanation.

The custom of leaving theory to researcher and practice to teachers has become dysfunctional (Clarke 1994) in Brown (2000). A practitioners/ teacher made to feel that he or she is the recipient of a researcher/theorist’s findings and prognostications with little to offer in return.

There are some suggestions for joining the community of theory builders:

1.      Play both believing game and doubting game.

Most scholarly traditions are involved in what is called the (doubting game) of truth and seeking: trying to find something wrong with someone’s claim or hypothesis. The important of the (believing game) n: trying to find truths not errors.

2.      Appreciate both the art and science of SLA.

There are two traditions in research. The first is Nomothetic and second one is hermeneutic. Nomothetic provides us with scientific methodology and prediction, while hermeneutic provides us with a means of interpretation and understanding. 

3.      Trust (to some extent) your intuition.

Physiological research on cognitive styles has shown us that people tend to favor either an intuitive approach or an analytical approach to a problem. There is evidence that good language teachers have developed good intuition. But how do you learn intuition?

a.       You need to internalize theoretical foundation.

b.      There is no substitute for the real experience.

c.       You must be a willing risk- taker.

Teachers of second language students are faced with many challenges and often have questions about how to best teach these students. There were so many theories in this area that talked about SLA. Now, people might say, “Well, how do I apply so-and-so’s theory in my classroom?”  There are also some common questions in learning English as a second language, those include:

• How long does it take to learn a second language?

• What do we know about second language learners?

• What influences the learning of a second language?

• What can I do in my classroom to facilitate the process of second language acquisition?

• What should I expect the second language learners in my classroom to be able to do?

            Researchers give many skills to the teacher in: program developing, textbook, writing, observing, measuring, variables of acquisition applying technology to teaching. According to Krashen Hypothesis, these are some strategies that can be used by the teacher in teaching second language:

·        Showing pictures or visuals to accompany new vocabulary words and Communicative concepts.

For example, a math lesson on multiplying and dividing negative and positive numbers should incorporate pictures of the positive (+) and negative (-) signs, as well as the symbols for multiply and divide. A history lesson on Columbus sailing to the New World should incorporate pictures of Columbus, the ships, maps and the Taino Indians. In wood shop, rather than just telling the students what the tools are and what they can do, the teacher can hold up the tool or point to the tool as he/she says the name and demonstrate the tools capabilities. Additionally, the teacher can provide second language students with pictures of the tools next to which the students can write the name and use of the tool to use asa study guide.

·        Incorporating gestures, drama and music into the lessons

Listening to rhythms and music and physically acting out situations makea lesson more comprehensible and memorable. To better illustrate the experiences of the first English colonists in Virginia, the teacher might have students act out the situation using their new vocabulary and using facial expressions to demonstrate the feelings of the colonists. The American states can be taught through songs such as “The United States.” which rhythmically introduces the students to the name of each state. Carolyn Graham has produced a number of books for English language development which use these rhythmic “jazz chants” to emphasize different grammar rules.

·        Designing lessons with hands-on activities and manipulatives.

Science and math are ideal subjects for incorporating hands-on activities and manipulatives. In math class, the teacher can demonstrate the concept of perimeter and area by having students place a string around different sections of grid paper. The string represents the perimeter and the squares within the grid paper represent the area. To study the planets of the solar system in science class, the teacher can help students measure out a scaled representation of the distances between planets outside on the playground. Students can then represent each of the planets and find out why different planets take different lengths of time to complete their orbits. An English

or history lesson can utilize pictures and props to support the new vocabulary and the plot of a story. To check for comprehension, the teacher might have students place the pictures in order and describe the pictures using the newly learned vocabulary. In geography, the teacher or the students can design a floor puzzle of the United States consisting of 50 pieces, each one a different state. Students can work jointly on putting the puzzle together. As well, the teacher or students can design a floor map of the world and students can stand on the different continents as the teacher says their names.

·        Repeating new vocabulary.

The teacher repeats vocabulary crucial to the understanding of the lesson in a variety of ways: 1) games where students place the written vocabulary word on the corresponding picture or write the word as the teacher holds up the picture; 2) board games such as trivialpursuit, vocabulary, scrabble, boggle or hangman; 3) computer assisted lessons that incorporate the new vocabulary.

·        Translation.

When the second language group is homogeneous, the teacher can quickly translate key concepts to make the lesson comprehensible. However, the teacher should not come to rely upon translation as a common teaching tool in her second language classroom, as the students will learn to direct their attention to the translation rather than the target language.

In constructivist, simply stated that learning second language is a learning process which allows a student to experience an environment first-hand, thereby, giving the student reliable, trust-worthy knowledge. The student is required to act upon the environment to both acquire and test new knowledge.

CONCLUSION

In shorts, the above discussion can be summarized into several points.

Innatist theory first of all states that conditioning model is not appropriate to explain how human language is acquired based on the fact that children can produce novel sentences in new combination that has never been heard. This theory centers on the existence of LAD/UG. Many research support the existence of natural order of morpheme acquisition.

Innatists never talk about reinforcement, but as interaction always involves responses that can be reinforcement, we can say that reinforcement plays roles especially in maintaining the language.

Cognitivist view sees that in acquiring a language, a human being need a mental capacity. However, this is not the one specific for language acquisition. This is the same mental capacity to learn mathematic and how to cook. As a matter of fact, in the discussion, the dominant topic is on how knowledge is perceived, stored and retrieved.

When the learning of the new language takes place in informal setting, Krashen hyotheses are acceptable. When the learning is in formal setting, behaviorist view and cognitivist view can be used explain the process more adequately.

Constructivism is a theory of learning and an approach to education that lays emphasis on the ways that people create meaning of the world through a series of individual constructs. Constructs are the different types of filters we choose to place over our realities to change our reality from chaos to order.

In summary, all the theories are complementary and useful for us to understand the nature of second language acquisition.