The next post in this series (#3/9), The Acquisition/Learning Hypothesis, is found here.


M: The Monitor Hypothesis

“Knowing grammar rules can help students to monitor their speech and correct themselves.”

The first of Krashen’s hypotheses we will discuss here is the monitor. This is for two reasons. First, every conversation among language teachers ends with discussing a point of grammar. We like language and we like figuring out how it works. We went into language teaching because we enjoy the nerdy side of it like debating the finer points of obscure grammar.

The other reason is that whenever comprehensible input is mentioned concerns are raised about the role of explicit grammar teaching. Putting the monitor hypothesis first helps to allay the fear that students will not know any grammar or that you think it is unimportant.

Grammatical knowledge does not correlate completely with fluency, but it can be helpful in some situations. Explicit grammar study can serve a purpose, but it is limited. When students are consciously aware of grammar they can sometimes monitor their language use and make corrections as they write, and to a lesser extent, as they speak.

For this internal monitor, or self-check, to work three conditions must be met. The student must:

  1. Know the rule
  2. Be focused on the rule
  3. Have time to apply the rule

These conditions rarely occur when using the language outside of the classroom. They normally happen only on tests in class that are focused on a particular aspect of grammar—and then students promptly forget them.  Here is why these conditions are difficult to achieve in real world use outside of the classroom:

  1. On knowing grammar rules: Language is so complex that even PhD’s that study the subject do not know all of the rules of grammar. New grammar rules are discovered every year. Professional linguists would admit that no one knows all of the grammatical rules of the language they use, but with use, the subconscious mind puts most of it together.
  2. On focusing on grammar rules: In real language use one rule is hardly ever the focus. Many verb tenses and multiple aspects of grammar are used, even when talking with young children.
  3. On time to apply grammar rules: When you are speaking there is hardly ever time to think about the grammar formulas or rules—what you have acquired will come out. Language that is acquired subconsciously comes out spontaneously.

Explicit grammar teaching tends not to stick with most students. Why? Because explicitly taught grammar is rarely contextual or meaningful. Grammar rules have traditionally been taught as units. The rule is presented, practiced, drilled, tested… and then quickly forgotten. This is an ineffective strategy for long term memory with language, let alone acquisition. The human brain picks up language piece by piece and repeated over time, rather than all at once. Meaningful, comprehended, spaced repetition is what works; not all of one grammar point in one lesson. Enjoying regular, nutritious, tasty meals rather than trying to eat a pickup truck full of food once a month is what works to make your body healthy. The same thing goes with acquiring language—learning little by little is best.

Krashen and many other SLA researchers assert that language acquisition is mostly an unconscious process, and therefore the use of the monitor is limited. Self-monitoring can be helpful when there is time to reflect and edit one’s own work, as in writing a formal essay when there is time to think, time to write, reread, think again and rewrite. The older students get and the more fluent they become, the more conscious knowledge of grammar rules can help them to monitor their own speaking and writing because they can think more abstractly. Formal teaching of grammar has little place in beginning language classes or with elementary aged students. Grammar study can sometimes be helpful with upper level high school students and with college students because those students can analyze and compare grammar and have more developed meta-cognitive abilities. But keep in mind that explicit grammar teaching is not necessary to develop fluency.

One area where many teachers think that explaining a rule and drilling it may be beneficial is in teaching advanced grammatical structures such as the subjunctive mood in Spanish, French, Latin and other languages. But Krashen’s research indicates that the only factor that influences mastery of the Spanish subjunctive is the amount of reading of novels the students has done, and not (surprisingly, to most students and instructors) the amount of formal study, or even the time spent in another country (!).



  • Teach grammar to the appropriate students. Young students need no grammar instruction. Older students can benefit from some grammar instruction to answer nagging questions compare to L1, and as an introduction to linguistics.
  • Teach grammar minimally. Teach grammar sparingly, realizing that it does not really help to develop fluency. Use correct grammar and point out how it is being used at the level of the sentence, but limit grammatical units.
  • Ask the whole class questions and expect a choral response. Use regular scaffolded comprehension check questions to the whole class to get a general sense of student understanding. The confidence, volume and speed with which the class answers can be a good indicator of general comprehension.
  • Ask individual students questions. Use differentiated comprehension check questions to individuals based on their level of understanding and self-reflection.
  • Check acquisition with timed writing. Have students write essays from time to time. Start with timed writing of stories they are familiar with to give them confidence.
  • Let students use the monitor. Occasionally give student time to write, read and rewrite their essays so that they can use their own internal monitor.


The next post in this series (#3/9), The Acquisition/Learning Hypothesis, is found here.


NOTE: This is a series of short posts on Stephen Krashen’s 6 main hypotheses of language acquisition, presented in a simple form. I teach these ideas in this same way to my high school students. We even have quizzes on each of the hypotheses. It helps students to know something about linguistics so that they understand WHY certain methods are being used in class—that the teacher is not just making up activities, that what is being done in the classroom has a basis in theory, research, and successful practice. I also want to prepare them to be able to identify best practices in language courses they may take later.
We use the acronym MANIAC to remember the 6 hypotheses and because a teacher may need to focus like a maniac in order not to be swayed by the inertia and tradition in education. Don’t worry about the “maniac” moniker, you’ll get maniacal energy from your engaged and acquiring students once you learn how to put these hypotheses into action.