Stephen Krashen's L2 learning theories

Stephen Krashen (University of Southern California) is a noted linguistics expert. His research specializes in how we learn languages and develop reading, speaking and writing skills. Much recent research is about non-English and bilingual language acquisition. However, he has also researched grammar acquisition in both native and non-non-native speakers. During the past 20 years, He has published over 100 books and articles and has been invited to deliver over 300 lectures at universities throughout the United States and Canada.

Following is a description of his widely known and well accepted theory of second language acquisition. Krashen's work has had tremendous influence on second language research and teaching. As a result, the "prescriptive" (rule learning & memorization) approach has largely been abandoned in favor or "descriptive" (competency and producing meaning) approach.

Krashen's theory of second language acquisition consists of five main hypotheses:

• the Acquisition-Learning hypothesis
• the Monitor hypothesis
• the Natural Order hypothesis
• the Input hypothesis
• the Affective Filter hypothesis.

The Acquisition-Learning distinction is the most fundamental of all the hypotheses in Krashen’s theory and the most widely known among linguists and language teachers.

There are two independent systems of second language performance: 'the acquired system' and 'the learned system'. The 'acquired system' or 'acquisition' is very similar to how children acquire their first language. It requires interaction in the target language - natural communication. Speakers concentrate less on form and more on communication.

We associate the 'learned system' or 'learning' with formal instruction. It is a conscious process that results in conscious knowledge 'about' the language. Learning grammar rules would be one example. According to this theory and set of hypotheses, ‘learning' is less important than 'acquisition'.

The Monitor hypothesis explains the relationship between acquisition and learning. It also defines the influence of learning on acquisition. The monitoring function is a direct result of learning grammar and rules. Communication or creating meaning comes from the acquisition system. The learning system 'monitors' or 'edits'. The 'monitor' acts in a planning, editing and correcting function when three specific conditions are met: that is, the second language learner has sufficient time at his/her disposal, he/she focuses on form or thinks about correctness, and he/she knows the rule.

It appears that the role of conscious learning is somewhat limited in second language performance. The role of the monitor is - or should be – minor: it should be used only to correct deviations from 'normal' usage and to give speech or writing a more 'polished' or polished appearance.

Individual language learners vary in 'monitor' use. Some learners use the 'monitor' all the time: they are "over-users." Those who have not learned or who prefer not to use their conscious knowledge are under-users. Those using the 'monitor' appropriately are optimal users. Extroverts and the over-confident are more likely to be under-users. Introverts and perfectionists are over-users. Also, over-use of the 'monitor' may reflect a lack of self-confidence. Those who worry so much about making mistakes that they can hardly speak are monitor over-users.

The Natural Order hypothesis is based on solid research suggesting that acquiring grammatical structures follows a predictable 'natural order'. For a given language, some structures tend to be acquired early while others late. This order appears not to depend on the learners' age, L1 background, or how they are exposed to the language. Obviously, studies do not agree 100% on every detail. However, statistically significant similarities reinforce the existence of a Natural Order of language acquisition. Krashen explains that a natural order hypothesis does not mean that a language syllabus has to follow the order in the studies. In fact, he rejects grammatical sequencing when the goal is language acquisition.

The Input hypothesis explains how learners acquire a second language. This hypothesis explains of how second language acquisition takes place. So, the Input hypothesis is only concerned with 'acquisition', not 'learning'. According to this hypothesis, the learner improves and progresses along the 'natural order' when he/she receives second language 'input' that is one step beyond his/her current stage of linguistic competence. For example, if a learner is at a stage 'i', then acquisition takes place when he/she is exposed to 'Comprehensible Input' that belongs to level 'i + 1'. Since not all of the learners can be at the same level of linguistic competence at the same time, Krashen suggests that natural communicative input is the key to designing a syllabus, ensuring in this way that each learner will receive some 'i + 1' input that is appropriate for his/her current stage of linguistic competence.

Finally, the fifth hypothesis, the Affective Filter hypothesis, expresses the view that a number of 'affective variables' play a facilitative, but non-causal, role in second language acquisition. These variables include: motivation, self-confidence, and anxiety. Learners with high motivation, self-confidence, a good self-image, and a low level of anxiety ‘pick up’ – learn or acquire - languages more easily. On the other hand, low motivation, low self-esteem, and anxiety can combine to 'raise' the affective filter. This creates a 'mental block' that prevents both the acquisition of comprehensible input and the production of meaningful output (communication). In other words, when the filter is 'up' it impedes language acquisition. However, positive affect is necessary, but not sufficient on its own, for acquisition to take place.

The Role of Grammar

According to Krashen, studying the rules and structure of a language can have general educational advantages in language programs. It should be clear, however, that studying irregularity, formulating rules and teaching complex facts about the target language is not language teaching, but rather is "language appreciation" or linguistics.

The only time teaching grammar leads to language acquisition (and proficiency) occurs when the learners want to know more about the subject. The target language is used as a medium of instruction. When this happens, both teachers and students mislead themselves into believing that studying grammar is necessary for learning another language. Put differently, "teacher talk" to explain grammar points is comprehensible input and student participation creates a learning environment for producing meaningful output. Also, the filter is low because conscious efforts are usually on the subject matter, on what is being talked about, and not the medium (English language).

This is a subtle point. In effect, both teachers and students deceive themselves if they believe that studying grammar is responsible for learning progress. Actually, reading about grammar, analyzing structures, thinking about how the structures work, and using the language are all input in the target language. That, not studying grammar, is what leads to learning progress. Other subjects that hold their interest would do the same – be a source of input, encourage meaningful output with minimum monitor interference, etc.