Anyone who says that they learned to read any language via explicit grammar instruction is lying. They don’t know that they are lying, though, so it’s not their fault.

Instead of grammar enabling them to read, they were actually exposed to understandable messages over time, even if their own focus was on explicit grammar. In other words, grammar knowledge wasn’t the cause of understanding what they read, but instead was a byproduct of studying Latin the way they did. All they needed in order to read Latin, however, was to know what words meant, and to keep reading them in different contexts. They might think that studying grammar worked, but it didn’t, and it wasn’t necessary. It’s not the grammar, it’s what was going on while studying grammar. Some still say grammar is necessary.

Two Counter Examples You Don’t Need To Research
1) If explicit grammar knowledge is necessary to read, no human would be able to read before age…10? Actually, I keep hearing that grammar isn’t taught in schools anymore anyway, a lament coming especially from Latin teachers who say that their students don’t know English grammar—oh wait—that’s right…kids don’t know grammar but they can read English?! Exactly. Now, as if that weren’t enough, some still…still somehow think grammar is necessary.

2) If explicit grammar knowledge is necessary to read, I should not be able to read French, a language for which I have had zero explicit grammar instruction. Either I defy nature as some kind of living deity (oh please let it be Mars), or grammar isn’t necessary.

So, as is often the case when studying Latin conventionally, people who say that they learned to read Latin via explicit grammar instruction committed paradigms and textbook “rules” to memory, and then “dealt with” texts typically well-beyond an appropriate reading level. They were so determined, driven by some internal or external motivation, that they either were constantly exposed to understandable Latin while engaging in the texts they were reading/translating, or just soaked everything up into their memory like a sponge without much effort. All this was happening below the surface level of that conscious grammar knowledge. It was there the whole time, but never seen as the cause of being able to read. The attention to grammar itself didn’t do anything. It was the constant exposure to Latin that’s required in a grammar-focused way of learning that did it.

So at best, this constant exposure to understandable messages over time resulted in an intake of that input which ended up “sticking” in their mind. This is known as acquisition. Given the uncanny memory of these folks, the messages didn’t require as many exposures as others The others are people less-determined, or with typical memory—hoi polloi (who have just as much a right to learn Latin, btw). Again, at best, they might be able to read now, but it wasn’t grammar that got them there.

At worst, however, the people who say that they learned to read Latin via explicit grammar instruction aren’t reading Latin at all, but instead are relying on that memory, remembering what they translated long ago. This possibility is scary. With enough sources and models to recall from memory, the result could look a lot like what reading actually is, but again, isn’t connected to that grammar instruction at all.

Another Example
In rereading Oerberg’s Lingua Latina Per Se Illustrata: Roma Aeterna, I have caught myself thinking “oh right, this is the part about the ___” without actually looking at the words and reading for meaning. In some cases, I fill in what’s coming next—in my head and in English—without moving along in the text! I actually must focus really hard in order to actually read some of the texts I’ve spent  hours engaging with, whether in undergrad, grad school, and beyond. I get the same result with certain Virgil texts I can recall from memory right now, only needing the start of a line or two to get me going. This isn’t reading, folks, and with a massive memory for particular paradigms and paragraphs of meaningful Martial and Marcus T., one can easily fool oneself into thinking one is reading! No wonder grammar is given so much credit!

At last, there is a neutral case being that people who say that they learned to read Latin via explicit grammar instruction can recall from memory and apply textbook “rules” so quickly that the process also looks a lot like reading. We know that few, few people do this, and whether aptitude and motivation play a role doesn’t matter; they still aren’t reading Latin, either.

Pedagogical Implications
Let’s face it, expliclty learning and teaching grammar was “working for us and our students” just fine until we started looking at 1) who we really were, 2) who our students really were, 3) what those measurements of success were, and finally, 4) who our students…weren’t! 

We might be lying to ourselves about how we got to where we think we are. So, if few students benefit from explicit grammar instruction—especially early on, and not in self-selected college programs—and we have a choice (free from external pressures), why would we choose the less-universal, more-exclusive practice?