Stephen Krashen is a linguist, educational researcher, and activist who is Professor Emeritus at the University of Southern California. In the 1990s, as the state of California became increasingly hostile to bilingual education, Krashen was instrumental in advocating the merits of learning a second language. His Acquisition-Learning Hypothesis is the centerpiece of his academic work.

Krashen’s Acquisition-Learning hypothesis revolves around the concept of “comprehensible input,” a term which essentially means “messages that can be understood.” Comprehensible input is best received when the learner is hearing something that he or she wants or needs to know. Krashen differentiates language learning from language acquisition, emphasizing that while learning is a formalized process, such as that which occurs in a classroom, acquisition happens informally, when a person is relaxed. He identifies a “silent period” during language acquisition, a time during which the student listens but is not comfortable speaking.

The Acquisition-Learning hypothesis acknowledges that students learn faster as they are given more comprehensible input. Inversely, a lack of comprehensible input delays language acquisition. Total Immersion Language Teaching, for example, succeeds so well is because it provides lots of comprehensible input. When people are immersed in a culture in which they do not know the language, they have an intense need and desire to speak that language. Such students are not interested in grammar lessons from a book but, instead, want to hear “comprehensible input” about that culture that teaches them what they need to know to survive.

Krashen’s acquisition-learning theory has much in common with both the communicative approach to language study and Noam Chomsky’s theory of generative grammar. The idea of “comprehensible input” is simply another way of saying that students learn languages best when they are learning about things that interest them. This idea is the essence of the communicative approach. Krashen’s Natural Order Hypothesis says that we acquire the rules of grammar in a logical order. This is similar to generative grammar’s hypothesis that the basic foundations of human grammar are deeply embedded in the human brain.

Stephen Krashen has been criticized for not having sufficient empirical evidence to back up his theories. Gregg accused Krashen of using “ill-defined terms.” McLaughlin critiques Krashen’s theories as being weak and imprecise. However, Krashen has conducted extensive research to determine the validity of his theories, and his dedication to promoting bilingual education has had undeniable worth. His frequent media appearances have pushed bilingualism to the forefront of public awareness.

Krashen is regarded true linguistic theorist, with over 30 years of research and hundreds of published articles and multiple books. Stephen Krashen’s passionate work has left an indelible mark on the future of bilingual education in America.

Some of Dr. Stephen Krashen’s research is available for free at www.sdkrashen.com, benikomason.net, http://web.ntpu.edu.tw/~lwen/publications.html, www.IJFLT.com.

Tracy Terrell and Stephen Krashen corporately developed the natural approach to language acquisition in 1977. They made an impact on the global community as this approach had an influence on many classrooms.

The goal of the natural approach is allow the beginner who is learning a new language to become an intermediate learner. It relies on the needs that the learner has.

Learning a new language using the natural approach is based on certain specifics, which include:

• The Acquisition hypothesis – this is where language acquisition is more important than language learning. Language acquisition develops more competence in the students and not so much the rules of the language as language learning do.
• Monitor hypothesis – this is the checks and balances of learning consciously.
• Natural order hypothesis – this is the grammatical structure that is usually expected and will do the student no good to learn them in another way.
• Input hypothesis – this is when students who are learning a new language are better able to comprehend it at a slightly higher level of competence.
• Affective filter hypothesis – this is when the student uses their emotions to block the input that is needed for language acquisition.

Some of the techniques that teachers can use to enhance the language acquisition using the natural approach is to allow students to speak when they are ready to do so, put students in group to foster more communication and use comprehensible input in student’s native language with gestures and other forms of articulation.

Students that use the natural approach are able to use the new language to indulge in meaningful conversations and activities.

Conclusion

It does seem from the approaches implemented by Krashen and the methods used by Terrell that students would learn to apply what they have learned more outside of the classroom and more by communicating with their peers.

This constitutes why students will learn language in a natural way when they can identify with others. The natural approach indicates that the more exposure to the new language that a student has then the more successful they will be.

Research shows that students learn better when they are afforded the opportunity to practice the language that they are trying to learn. They also have to practice at the level that they are comfortable with. This is referred to as Comprehensible Output.

However, Comprehensible Input is much more complex. It has to do with how students hear and understand instructions that are above the level of language that they are learning.

Here is an example:

Someone who may be learning English as a second language could be told to “Pass the book to Emily,” and be able to understand quite alright.

If the teacher would change the sentence to reflect a slight variation such as “Open the book for Emily,” then this new information would be added to the student’s comprehension of the language.

The teacher would have to give the student the new material that will utilize any previous knowledge that the student had.

As long as the student understands the message, the teacher would have accomplished the task of equipping the student with what is needed to learn the new language.

Comprehensible Input, formerly known as the Input Hypothesis, was initiated by Stephen Krashen, who was a linguist and instructor. Krashen uses the equation i+1 to explain how people move from one point of understanding language to the next.

The “i” in the equation would refer to previous language competence and the additional knowledge of the language that we have that depends on situations and experiences. The “1” in the equation would be representative of newly acquired knowledge.

There are two levels of learning new language using the Comprehensible Input method. One is the beginning level and the other is the intermediate level.

In the beginning level, most of the time in class is used for verbal input that is comprehensible. Teachers have to make sure that their speech is modified so students can understand. Teachers should not force the student to speak at this level. Emphasis on grammar is only initiated for students who go to high school or are adults learning a new language.

In the intermediate level, it is more confined to mostly academic subjects for comprehensible input. More of the focus is on the meaning of the subject than the form of the subject.

Conclusion

Comprehensible input is a not based on the natural order of teacher, but students will be able to comprehend the natural order by receiving the input.