How Many Years Does It Take to Learn The Code?

When you play an electric guitar it's pretty easy to understand the differences when describing the type. You've got T-types (Telecasters), S-types (Stratocasters), LPs (Les Pauls) and then a few sub-categories (double-cut, single-cut, etc.). Piece of cake. Even the Firebirds, Explorers, Jaguars, Mustangs, etc. are fairly easy to understand and visualize.

But it's a whole different world when it comes to acoustics. Every maker of acoustics seems to use their own nomenclature when it comes to sizes and models. And their "code" is nearly indecipherable. For example, C. F. Martin, perhaps the preeminent maker of acoustic guitars has a naming/numbering system that only the most die-hard of acoustic players recognizes immediately. The creator of the "dreadnaught/dreadnought" (even the spelling is confusing!) size and shape has designated that model as a "D." As in D-18, D-28, D-35, Duh. From there it gets arcane and mysterious. The common models are 00, 000, OM. But wait, there's more: The 000 and OM are the same size, but a different scale. Right. To keep moving the ball down the field, Martin has also made new models (SC) and tweaked existing sizes and shapes (DJr, 000-10E, etc.). What's a person to do?

Well, if every maker used Martin's conventions, it might be easier to understand, but Taylor, arguably Martin's equal in the acoustic marketspace, uses a completely different naming convention. They use a lot of "Grands" in their names: Grand Symphony, Grand Orchestra, Grand Pacific, Grand Concert, and so on. But they also have the Academy series, the K line, the GS Mini (Grand Symphony, but smaller) and so on. Taylor also serializes their lineup. So, they have the 100, 200, 300, 400, 500 and so on. I have a 322ce and a 652ce. Each number and letter denotes something. Yay. But can anyone remember them all? And there is size/shape overlap between the two companies, but it takes an advanced degree in comparative studies to chart them. What's a person to do?

I have been playing acoustic guitars for over 56 years. I am only now beginning to understand the "code" when looking at a guitar listing. Still, it's always a bit of a by-guess-by-golly crapshoot. For example, I own a Martin OMC-15ME. In fact, the full description of this particular guitar is "OMC-15ME Streetmaster in Weathered Red." Whew. I am probably mistaken, but the way I decode this is it's an Orchestra Model (OM) with a cutaway (C) in size 15 made of Mahogany (M) with electronics (E). At least that how I see it.

Fifty-six years it's taken me to partially decode this stuff. Why do guitar makers make it so hard?

You?re dead on right. Unfortunately you have to research each maker. I find it easiest to use Martin as a baseline. You have to ditch it when you get to jumbos.
I classify things as
0
00
000 same as below but with 12 fret join
OM same as above but with 14 fret join
D
J (as defined by Guild)

English translations
0 - Parlour
00 -concert
000 and OM - orchestra
D - dreadnaught
J - jumbo

Agreed. It can be hard to figure out what you're looking at to compare apples to apples between manufacturers.
Martin is not bad as far as their naming conventions go - take Black's list, then take the numbers, which have their own connotations - 18 is a mahogany back & side, 28+ is rosewood, with increasing levels of decorations. (the 35 is the 3 piece back, compared the the rest are 2peice.
Taylors are harder to learn, but when you do it's easy to tell the differences. When I used to sell guitars I could tell you all the levels, 100-series, 200, 300 etc. and the sizing, which is the tens and ones place.
Then there are Gibsons, which just have different names - none of which really mean much to the appointments. And harder is ones that have the same name but different woods - there's J45s with mahogany and J45s with rosewood.
I worked at Guitar Center (20+ years ago, before they became the evil monolith they are now; in my day we took pride in knowing the equipment we sold. That was before they sold to the venture capatalist, much less whoever owns them now.) so I don't really know as well the smaller builders, but in those days I knew Martin, Taylor, Gibson, Larrivee, Takamine, Ovation, and a few others.