This is part of an answer to a question I provided @ Enotes.com
Deductive and inductive teaching of grammar
In TEFL (teaching English as a foreign language) there are two theoretical models of teaching: inductive and deductive. As theoretical models, they basically mean one thing: neither of them is better than the other, and the teacher ultimately chooses the one he or she thinks is best.
Deductive teaching will move from the general to the specific. You show a typical example of a sentence, for example, and then you break down the lesson into smaller, more in-depth segments. You will present the grammar rule first, then show examples.
Inductive teaching will do the opposite. Teach the segments first, as concepts, and then apply them to a bigger example. Along the way, you ask students whether they can identify patterns, concepts, connections, and similarities from what you taught previously to what you are teaching now. You will first show examples that illustrate a grammar rule.
A seasoned teacher will probably agree that the best methodology depends on how much time you have to teach, how many students you have, and the level of motivation of the students.
Implicit and Explicit
Since language has to be understood both explicitly and implicitly, teachers of language must take this into consideration when teaching. However, this is an ongoing debate in the TEFL field that runs the way the “nature versus nurture” debate runs in Psychology.
Explicit instruction involves explaining rules, providing “metalinguistic feedback” (asking if something is correct or incorrect), comparing and contrasting language, and having students repeat things.
Implicit instruction is teaching the language without rules or forms. The teacher uses the rules and forms of grammar spontaneously throughout the teaching. The students will recognize the patterns on their own and apply them.
Arguably, if you are left alone in a foreign country, you have no other choice but to learn implicitly. In contrast, if you have the means to hire a private tutor, chances are that you learning will be both explicit and implicit. The point is this: You will learn either way!
Pros for explicit instruction
Explicit instruction clarifies any doubts in grammar usage and application, whereas inductive instruction runs the risk of the student confusing a rule or applying it erroneously due to the specificity in the initial instruction.
Pros for implicit instruction
Implicit instruction happens more naturally and may elicit more interest and motivation from students who prefer to learn independently and by discovery.
All this being said, it is clear that grammar should be taught, whether explicitly or implicitly. It should be taught because according to theory,
- humans are born to understand it
- humans can make the connections
- all languages possess a grammatical blueprint (in theory)
- communication should be taught complete with the internal and external elements.