What it means to ‘know grammar’ and why this is important

Introduction

Here’s an issue which crops up when a teacher says something like this to me “But students have to know grammar to speak and write properly. If we don’t teach the rules, how will they learn the grammar.” So let me look at this and try to clarify what knowing grammar means and how we might help students ‘know grammar’ in a useful sense.

When language teachers talk about knowing grammar, what do they mean? It could mean either the ability to explain rules, or the ability to use rules fluently and accurately in real-time communication. Or both!

Declarative versus Procedural Knowledge

Declarative knowledge refers to factual knowledge - knowing that something is the case. In the context of grammar, it’s the ability to state rules explicitly: for example, knowing that, in English, we use the third person singular -s in the present simple (e.g., “She runs every day”). It’s the kind of knowledge often gained through formal instruction, textbooks, and grammar explanations. Teachers often give rules, show examples of the rules in practice (not necessarily in that order), then get students to practise the rules. The idea, is of course, that the rules come to stick and students can apply them to future situations. This is the principle of PPP - Presentation, Practice, Production.

In contrast, procedural knowledge is about knowing how to do something. It’s implicit, often subconscious, and equates to skill. We might just call procedural knowledge skill. A learner who has proceduralised a grammatical structure can use it accurately and fluently in spontaneous speech or writing, without necessarily being able to explain the rule behind it. For example, native speakers usually produce grammatically correct sentences without ever having learned the rules formally. Ask me to explain why I said ‘I have played the drums for 50 years’ versus ‘I’ve been playing the drums for 50 years’ and I would struggle.

The Interface Issue

A key question for researchers and teachers alike is: Can we turn declarative knowledge into procedural knowledge, or knowledge into skill. Most teachers think you can. This is known as the interface question, and it has generated extensive debate over the years. There are three main positions in the debate:

1. No-interface position (Krashen, 1981): This view argues that explicit knowledge of grammar (declarative) cannot turn into implicit knowledge (procedural). According to Krashen’s Input Hypothesis, language acquisition happens subconsciously through exposure to comprehensible input, and explicit grammar instruction only contributes to conscious learning, not true acquisition. Note that Krashen does not argue that declarative knowledge is useless, but that it only helps us monitor our accuracy. You have probably done this many times as you stop to think which grammatical or lexical  choice is correct. You may ask: how do studnets learn grammar in this way? It's a fair question. Whereas it is clear that many language learners acquire a very good grasp of language withour explicit instruction in grammar (think of immigrants, for example), it is much harder for school students to do so, given their limited contact time and lack of further input outside the classroom.
2. Strong-interface position (DeKeyser, 1998): Robert DeKeyser and others argue that declarative knowledge can become procedural through practice. Just like learning to ride a bike or play an instrument, learners can automatise grammar rules through repeated meaningful use. From this perspective, grammar instruction is valuable as a starting point that must be followed by extensive practice for proceduralisation to occur. Even DeKeyser, however, has noted that automatisation is difficult and may not be possible for some learners, especially younger ones or people with lower language learning aptitude. 
3. Weak-interface position (R. Ellis, 2005): This more nuanced view suggests that declarative knowledge may assist procedural development under certain conditions. Factors such as the learner’s age, aptitude, and the complexity of the structure all influence whether and how explicit knowledge contributes to fluency. This messier view of the interface may be the best reflection of reality. Interestingly, brain research shows that explicit, conscious learning occurs in different parts of the brain to implicit, subconscious learning. Does this mean that the two are totally distinct and that one cannot become the other? Bill VanPatten has argued that no mechanism has been described to explain how this might happen. In contrast, Nick Ellis has described a sort of dynamic interface between explicit and implicit knowledge. The fact is we don’t know how this works.

Implications for Teaching

Understanding the interface between declarative and procedural knowledge has practical implications for grammar teaching. If we accept that automatisation is possible (and some classroom-based studies and personal experience suggest it is), then grammar instruction should be much more than rule presentation. It should involve opportunities for practice, automatisation, and meaningful use. This may include elements of PPP .moving from controlled practice to more open-ended tasks.Techniques such as structuring input to make grammatical constructions more noticeable, focused communicative tasks, and production-based practice (‘pushed output’j can help bridge the gap between declarative and procedural knowledge.

However, it’s also important to recognise that some students benefit more from explicit instruction about grammar than others, and that different grammatical features may be automatised at different rates. Many may be impossible to automatise at all given the limited time we have with classes. Don’t forget also that research is clear that some grammar is naturally acquired much more slowly and is inherently harder to learn, partly because of its complexity, partly owing to differences with first language grammar. 

My own (long) experience was that teaching rules was of limited value to most students, and that you had to severely limit which rules you give. Students benefitted much more from just comprehending and using language, acquiring a repertoire of oft-repeated chunked language they could deploy and adapt, partly for exam purposes. In general, my advice would be that teachers should combine occasional, concise grammar explanations with abundant exposure and interactive use, tailored to specific classes. A key teacher takeaway from this is that proficiency develops far more through using the language than talking about it.

In everyday pedagogical terms, the range of grammar practice activities is large and there is nothing much new under the sun in this regard. Researchers suggest that meaningful practice (e.g. using information gap tasks to force students to use constructions) is better than mechanical practice (e.g. simple transformation drills). But even mechanical drills may have a place with some classes. Otherwise teachers can use question-answer, gap-fills, translation, substitution and transformation drills, and games. The more enjoyable the activity, the better. Much depends on factors such as the class dynamics, aptitude, teacher skills and beliefs. The nature of the syllabus and the exam are key influences.

After analysing many studies into classroom grammar teaching, one respcetd scholar, Frank Boers concluded that brief, up-front explanations of grammatical rules may be the best solution in many cases. In his excellent book (Boers, 2021) he concludes:

He argues that because there are so many variables involved in classrooms, it’s “probably wise to adopt an eclectic approach”. Below is the sequence he describes which is evidenced by research:

1. Draw learners’ attention to a target words/phrases/pattern. 

2. Explain the meaning or function of the items/pattern with the aid of examples, or, if thought possible without a high risk of confusion, ask the learners to work them out themselves with the aid of examples, and then confirm.

3. Engage learners in content-oriented activities with input texts that further illustrate the use and meaning of the items/pattern. 

4. Possibly elaborate briefly about a property of the item that may make it easier to remember.

5. Provide opportunities for the students to retrieve the items/pattern from memory. This can be done in diverse ways. For example, a modified version of the input texts from step 3 could be used to cue recall of missing items (e.g. gap-fill). In the case of certain grammar features, it could be done through the kind of interpretation practice proposed in Processing Instruction (exercises which force students to make form-meaning links with the grammar, for example a verb ending). Recall of meaning can be prioritised if the aim is to encourage receptive knowledge; recall of form if the aim is to foster productive knowledge. 

6. Engage students in communicative tasks likely to elicit the target items/pattern. Ensure opportunities for improvement (e.g., feedback) between the tasks or task repetitions. Although there are more language-focused steps in this ensemble (steps 1, 2, 4 and 5), the content-focused activities (steps 3 and 6) would take up more time, thus creating a balance overall between the 2 broad approaches.

You should find little controversial in the above approach..

Integrate grammar teaching into content-focuseed work or teach it separately?

Most teachers feel instinctively that grammar is best highlighted and practised within the context of topical or content-focused work. The old idea of the 'grammar lesson' feels out of date. That would be my line too, but there may be occasions when it makes sense to just 'teach a grammar structure' in isolation. An example from my own experience was the French subjunstive, usually taught to advanced classes. The subjunctive is complex in many ways, but students seem to appreciate having its form and use laid out clearly and with opportunities to practise examples. My expereince was that motivated students would then incorporate the subjunctive into their speech and writing, to the point that it became embedded or 'acquired' (to use Krashen's terminology). As usual, it is wise to return to the structures in question repeatedly at latre dates, in line with the widely accepted pronciples of spaced learning and retrieval practice.

Spada and Lightbown (2008) looked into the question of teaching grammar in an isolated or intergrated way and found that teachers and students see the benefits of both types of instruction. Valeo (2018) found advantages to both types of instruction. Think of this from the student's point of view: some classes might welcome the clarity and challenge of seeing the whole grammatical picture without being distracted by other input such as new vocabulary or content.  As is often the case in our field, there are few hard and fast rules when it comes to teaching grammar.

Can you have your cake and eat it?

So we don't know for sure how useful grammar instruction is and to what extent it is possible to turn knowledge into skill. But what if grammar-focused activities also contain a lot of comprehensible input? This is the case where the target language is used for a large proportion of time, but where input is flooded with examples of constructions you want to target. Teachers do this a lot, choosing texts which force students to see, hear and use structures. Provided the input is interesting, you are allowing students the opportnnity to both 'learn grammar' and use language input which we know is the foundation of all language acquisition.

An objection to this view is that when grammar is at the forefront of the teacher's mind, the input and activities are bound to be compromised as students are asked to focus on the form of the message alongside its content. Researchers tell us that it is hard to do both at the same time.

Conclusion

To 'know grammar' is not simply the ability to recite rules; it is to be able to use those rules fluently and accurately in real-world contexts. Declarative knowledge may serve as a foundation, but without proceduralisation, it remains of interest, but ultimately of little use. As research into the interface between knowledge and skill continues to evolve, one thing is clear: effective grammar teaching must support the transition from knowing about language to being able to use it. As Pawlak (2019) states, citing Nassaji and Fotos (2011):: "... teachers should be eclectic in their pedagogical approach." My feeling is that many teachers are over-optimistic about the capacity of students to turn their knowledge into skill.

References:

Boers, F. (2021). Evaluating Second Language Vocabulary and Grammar Instruction: A Synthesis of the Research on Teaching Words, Phrases, and Patterns. Routledge.

DeKeyser, R. (1998). Beyond focus on form: Cognitive perspectives on learning and practicing second language grammar. In C. Doughty & J. Williams (Eds.), Focus on Form in Classroom Second Language Acquisition (pp. 42–63). Cambridge University Press.

Ellis, N. C. (2005). At the interface: Dynamic interactions of explicit and implicit language knowledge. Studies in Second Language Acquisition, 27(2), 305–352.

Ellis, R. (2005). Measuring implicit and explicit knowledge of a second language: A psychometric study. Studies in Second Language Acquisition, 27(2), 141–172.

Krashen, S. (1981). Second Language Acquisition and Second Language Learning. Pergamon Press.

Nassaji, H. and Fotos, S. (2011). Teaching grammar in second language classrooms... New York and London: Routledge.

Pawlak, N. (2021). Implicit versus explicit grammar learning and teaching. In Debates in Second Language Education (Macaro and Woore, 2021). 

Spada, N. and Lightbown, P.M. (2008), Form-Focused Instruction: Isolated or Integrated?. TESOL Quarterly, 42: 181-207.

Valeo, A. (2018). Isolated Versus Integrated Form-Focused Instruction. In The TESOL Encyclopedia of English Language Teaching (eds J.I. Liontas, T. International Association and M. DelliCarpini).