This module is a narrative description of the most important theories of second-language acquisition that establish the basis for evaluating the effectiveness of instructional methods and approaches for bilingual and English Language Learners. Most of these theories are attributable to Professor Stephen Krashen, Emerita of the University of Southern California.

Learning vs. Acquisition Hypothesis

The learning versus acquisition hypothesis (Krashen, 2003) states that there is a difference between acquiring a language through use of the L2 in everyday interactions for the purpose of communication as opposed to formal study of the language, such as in a foreign or second language course. The implication of this theory is that both processes support rapid and thorough L2 development, but that formal language learning alone often fails to produce full bilingual proficiency where the learner can use the language in a variety of natural settings and contexts. This theory has implications for ELL who are learning English in school and where English is used as the medium of instruction while also being the learners’ L2. In this situation, the learners are not studying the language as a subject. Rather, they are expected to learn grade-level academic content through English, despite the fact that their English proficiency is not fully developed.

Natural Order of Acquisition Hypothesis

This theory articulates our best understanding of how L2 is acquired by observing the order in which usage of certain grammatical and syntactic forms emerge in the L2 learners’ language production. In many cases, the emergence of forms in L2 follows much the same pattern or sequence as in developing L1. The sequence moves from simple, concrete and regular forms (regular verbs, simple negation) to more complex and abstract forms (compound verbs, conditional tenses). We also observe that more frequently used and common grammatical forms, even though they are irregular, emerge at the early stages of L2 acquisition. Consequently, we can look for certain forms at different levels of developing language proficiency (De Avila, 1997). This natural order of acquisition is in part what makes language assessment possible since it helps us to describe the characteristics of L2 learners’ developing language.

A second dimension to the natural order of acquisition hypothesis that informs dual language instruction is the varying rates of growth of the four skills of language: listening, speaking, reading and writing. We know that the learning curve for each of these skills is not is it that we delay reading and writing instruction in our public schools until children are five or six years of age? In part, this is because of maturational factors involving children’s abilities to sit still and concentrate in school, but there is also a linguistic reason. We begin reading and writing instruction at the point when children have well established oral language skills in their native language and the cognitive maturity to begin to analyze language as a system. The implication for students who are becoming literate initially in their L2 or are learning to read and write in L2 after acquiring literacy in their L1 is that listening and speaking, the oral skills, will develop at a faster rate than reading and writing. The theory also draws our attention to the fact that there are receptive skills (listening and reading) and productive skills (speaking and writing) and that these also grow at different rates. This is because production requires the integration of many features of the language into performance of communicative and academic tasks. Therefore, reading and writing are more demanding on the learners’ linguistic resources.  We must keep the different learning curves for listening, speaking, reading and writing in mind as we plan programs and instruction for bilingual learners and as we assess their growth in language proficiency and academic learning over time.

The Interlanguage Hypothesis

Another theoretical orientation that aids biliteracy teachers in understanding L2 learners’ developmental progression and stages of emerging L2 fluency Linguists often refer to the developing second language skills of bilingual learners with its imperfections in grammar, syntax and range of vocabulary as interlanguage (Ovando & Collier, 1998). The term interlanguage was coined by Selinker (1972) who defines it as “…a separate linguistic system based on the observable output which results from a learner’s attempted production of a target language norm.” (p. 214). Five central processes form this system: language transfer, transfer of training, strategies of L2 learning, strategies of L2 communication, and overgeneralization of target-language linguistic material. Bilingual learners’ interlanguage system has its own internal logic, with the L1 playing an influential role in the formulation of interlanguage grammar. The developing L2 of bilingual learners can be assessed and scaled using language proficiency measures and rubrics applied to samples of oral and written language. Interlanguage analyzed and described in terms of patterns of errors and hypotheses formed about the origin of errors. This process is similar to miscue analysis in reading (Goodman, 2003).

Monitor Hypothesis

The monitor hypothesis (Krashen, 2003) states that as learners develop skills and competence in L2, they begin to correct and modify their speech and written production to conform more exactly to the model speech of native speakers of the target language. This occurs because they have a growing awareness of their own approximations and become better at “hearing” the differences between language input they receive and their own formulations of language sounds and grammatical structures. The development of the monitor requires time, a focus on linguistic forms, and a growing knowledge of the rules and patterns of L2. The monitor is possible because all languages are rule-governed systems and learners either implicitly or explicitly learn these rules in order to duplicate the system that characterizes a specific language. The monitor is an unarticulated function of metalinguistic awareness, based on the reality that linguistic forms are patterned and predictable. As learners are exposed to greater amounts of comprehensible language and perceive how linguistic forms such as prefixes and suffixes or word order give clues to meaning, they build an internal model of “correctness” that then begins to shape their language production.

There are several instructional applications of the monitor hypothesis and the natural order of acquisition hypothesis considered together. First, the theory calls into question whether direct and explicit instruction in grammar can improve learners’ L2 production. Research indicates that grammar instruction helps foreign and second language students become aware of patterns and rules in the target language so that they can self-correct or search their “mental banks” for forms that follow the rules (De Avila & Duncan, 1987). However, we know that many people learn foreign languages without having ever studied formal grammar. We also know that L2 grammatical forms emerge in a predictable order regardless of what formal grammar studies the L2 learner may have had. Consequently, the amount and comprehensibility of linguistic input and the opportunities that L2 learners have to produce language, however imperfectly and haltingly, for communicative purposes appears to be the more powerful variable in determining the rate of progress toward full bilingual proficiency (Krashen & Terrell, 1983).

Comprehensible Input Hypothesis

The theory of comprehensible input (Krashen, 2003) posits that we learn L2 by connecting linguistic input to prior knowledge and known concepts. Unless the oral and written L2 input is meaningful, the input is simply “L2 noise” because we cannot increase our knowledge of the language by simply hearing a stream of sounds and words. In other words, to learn a language we must be able to connect the language forms to the ideas that they are intended to represent. This is because language is a set of abstract symbols used by members of a particular language community who have agreed on their significance. In L2 teaching contexts, this means that teachers must find ways to make the language understood through the use of real objects, pictures, films, etc. so that meaning is attached to the language. Krashen also proposes the “I plus one” formula for determining the level of linguistic input that best promotes growth. The formula states that teachers should modify their speech and the linguistic input to a level of complexity one level beyond the learners’ level of competence. This is so that the language of instruction is both comprehensible and challenging, but not difficult enough to be frustrating or too far above the learners’ abilities to process meaningfully. The amount and quality of L2 language acquisition depends on comprehensible input at one level of complexity beyond the learner’s level of linguistic competence. This theoretical construct serves as a guide in differentiating instruction for L2 learners according to their levels of language proficiency.

Affective Hypothesis

The affective hypothesis and its sub-theory, the affective filter hypothesis, inform L2 educators about the importance of motivational, psychological, emotional, and interpersonal factors in language learning. We know that to learn L2, students must be willing to take risks, to make mistakes and sometimes even to appear foolish as they attempt to express themselves. In fact, high levels of motivation or attitude toward learn L2 appear to be a more reliable predictor of rate and levels of attainment of bilingual proficiency than aptitude (Gardner, 1971) This theory also provides insight into the obstacles to L2 learning posed by what is termed the affective filter such as embarrassment, shyness, or negative attitudes about language learning or toward native speakers of the language. The filter acts as a block or barrier to learning because it reduces the level of comprehensible input or prevents the learner from benefitting from the available input. The affective filter may also prevent learners from practicing the language sufficiently to develop their productive skills.

Researchers observed differences in levels of bilingual proficiency according to two motivational socio-cultural factors: instrumental versus integrative (Lambert & Tucker, 1972; Gardner, 1973). An instrumental motivation is a desire to learn the L2 for specific and limited purposes, such as communicating with customers in their business who speak L2. These learners acquired a functional use of the language needed to meet their needs or goals, but they did not attain full bilingual proficiency. Contrarily, learners who were motivated to fully integrate into the society of L2 speakers’ reached a higher level of L2 proficiency because of their motivation to become indistinguishable from L2 native speakers. When L2 educators consider students’ bilingual and bicultural socio-cultural contexts where proficiency in their L1 is highly valued within the immigrant community, while learning English is also valuable for interacting with the larger society and an asset in social, economic and cultural integration.

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Reference

R.C. Gardner (1973) “Attitudes and motivation: Their role in second language acquisition.” In Oller, J.W. & Richards, J.C. (Eds.).  Focus on the learner: Pragmatic perspectives for the language teacher. Rowley, MA: Newbury House.

Lambert, W. E., & Tucker, R. T. (1972). Bilingual Education of Children: The St. Lambert Experiment. Rowley, MA: Newbury House.

Krashen, S.D., & Terrell, T.D. (1983). The Natural Approach: Language Acquisition in the Classroom. Hayward, CA:  The Alemany Press.