Evidence-based answer · Last updated · How it’s made
Across dozens of studies, the strongest and most consistent finding is that explicit grammar teaching (being told and shown the rules) tends to produce faster, more reliable gains than purely implicit exposure, especially for complex rules and in the short term — but gains from any single method fade over time without continued practice, and input-based practice (processing real sentences) plus meaningful output practice together work better than rule explanation or drilling alone. In short: learn the rule explicitly, then immediately practice using it in context, and revisit it repeatedly rather than expecting one lesson to "stick.
Answered for language learning in general. No specific language was set for this question, so the findings are drawn from general second-language research rather than one language’s literature.
Multiple comparative studies found that learners who were explicitly taught grammar rules (told the rule and given structured practice) outperformed learners who only encountered the grammar implicitly through exposure, at least on immediate or short-term tests.1,8,16
In plain terms
The more complicated the grammar rule, the bigger the advantage of explicit teaching over implicit exposure; for simple rules the two approaches perform more similarly.1,14
Example
Even when a teaching method produces clear short-term improvement, both explicit and implicit groups tend to lose some of that knowledge over the following weeks if there's no continued practice or reinforcement.1
Instruction that has learners actually process real sentences containing the grammar point ('structured input' or 'processing instruction') tends to be at least as effective as, and sometimes better than, instruction that just explains the rule and has learners produce output, particularly for improving comprehension.4,5,10,12,17,18
In plain terms
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Input-focused practice (reading/listening and interpreting sentences) tends to improve comprehension skills more, while output-focused practice (producing sentences yourself, speaking or writing) tends to improve production skills more; each type of practice mainly strengthens the skill it exercises.5,6,11
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Across many studies, the instructional approaches that worked best combined a short explicit explanation of the rule with meaningful practice using real input and output, rather than relying on rule explanation alone or immersion/exposure alone.6,13,15,18
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Correcting learners' grammar mistakes while they are actively using the language — whether through direct explanation of the error or through a corrected restatement of what they said — reliably improves their grammar accuracy compared to receiving no feedback at all.2,9,16
In plain terms
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Studies disagree on whether direct correction with an explanation or the gentler recast approach produces better long-term learning; some found explicit correction more effective over the long run, others found the more implicit recast approach won out, and the outcome seems to depend on the exact study design and how it measured learning.2,9,16
People do differ in a general knack for picking up grammar (often called 'language aptitude'), and this talent matters more when someone is learning through explicit rule-based instruction than when learning through natural exposure; it also matters more for younger learners in some contexts.3
In plain terms
Explicitly teaching learners about specific ways their native language handles a grammar point differently from the target language, and having them compare and contrast the two, can help fix errors that come from simply carrying over native-language habits.7,15
Example
Now pick something to do it with
Each of these opens an overview of the apps, courses and immersion material worth a look for that — filtered to exactly what the advice above points you at: