Dudette you totally missing everything important. Let's start with the at least 3 other examples already provided in this thread. The least of which was 1 page for just the languages table. And the other person who said they would expect their version to be 5 pages. So sure, 20 pages is certainly too much, but 800 words is probably not enough. But this actually isn't the important part.
Someone could certainly make multiple pages worth of tables, sure. And not the actual important bit... 'kay.
As for your publishing example, that shows that publishing content for WotC is not simple and straight forward. It shows that there are many more people, and costs involved, than just paying 25 cents per word. And my points that it's not about the words, but the opportunity cost. Publishing anything about one things means they don't publish something else.
There is a LANGUAGE part of the D&D core rulebooks. Whether they were to use a NEW system or an OLD system there would still be a LANGUAGE part of the book. The "Opportunity Cost", therefore, is not "We could have something new if they didn't waste time writing about languages" so much as "How much more words about language would be written?" instead. Which means, yes, it's -just- a matter of how many words they're willing to pay someone to write. 800, 2,000, whatever the count is.
This is not adding a whole new chapter on Boll Weevils or the agricultural use of undead on the Thaymount. Languages is already part of the book.
And no, I know very little about WotC's publishing process. But I do know my own publishing process as I've published multiple products over the years, most of the D&D related. It's never as simple as you made it sound initially. You process outline shows that.
The part where languages are handled exists pretty much exclusively between 4 and 5. Grabbing writers and assigning writing. Which is pretty much the only part the designers and writers take part in, unless something gets bounced back to them for not being up to standard.
That is, pretty much exclusively, the part where the writers do anything.
You are completely ignoring my other points that are even more important than the size or process. First, you admit this would only be used by a small number of folks. Not that you need me to support your idea, but if you want me to you're going to have to show my why it's a good business decision for WotC to spend resources on it.
Everyone's already going to buy the PHB and DMG so it doesn't really matter how much of the userbase uses that particular rule, much like Encumbrance which is ignored almost universally and is still in the book.
This is not a big "Business Decision" where the couple hundred bucks to pay a writer to write a small section of the book is going to wind up costing WotC Millions down the road. Or where people will refuse to buy the book because they don't like changing up how Language works away from Race Languages.
Well. There -will- be people like that. But, really, there's people like that about literally ANYTHING you write in the books, so it's a "Can't please 'em all" write off.
(Edit: and you completely ignored my whole section on Comprehend Languages and what it does to a detailed language system.)
I don't see that in any of the posts we've been doing but... what about it? Comprehend Languages and Tongues breaks language no matter what, so why worry that it would do it to a different language system than "Common + Races"?
I would also like to know, if a detailed language system is so important to world building and D&D, then why don't you publish your own version of it? There are several folks here who agree with you and perhaps might even collaborate in developing such. And since you believe publishing is so easy, you can publish it yourself and make a ton of money since it's so important to D&D that surely you will sell a million copies.
"Detailed" language system... I don't think you've seen my actual intention.
And because it doesn't matter if I publish the most perfect and widely used language system in the 3rd Party space, if it's not in the PHB most players won't be aware of it, and will continue to use the terrible "Race Language" structure.
Also... I've written official material for Level Up/A5e, 3rd Party material for Purple Martin Games and Josh Gentry, published my own book which is the biggest single book in the A5e 3rd party space, had articles in the Gate Pass Gazette and EN5ider.
A Million copies, though? That's Paizo and WotC territory. Not a small 3rd party publisher.
And you think a detailed language system would be more popular than character options? Forgive me if I'm wrong, but doesn't every survey done here on ENWorld or by WotC point to more character options always being one of the top wants?
Why do you believe that a language structure that isn't "Common + Races" is "Detailed"?
Why do you believe that having any language structure that isn't "Common + Races" is exclusive of additional character options?
I stand by my point, adding a detailed language system would be a bad business decision for WotC to spend any words on. But it's a great opportunity for homebrew. And even a good opportunity to publish on the DMsGuild.
I disagree. Both that it's a "Bad Business Decision" since anything in the PHB is going to sell regardless of whether it costs them $150 or $280...
And it's a terrible opportunity for Homebrew because while you can do interesting stuff in your own settings (And I do use a simple language system in my settings that is different from Common+Races) it won't touch the cultural weight or momentum of whatever the PHB says.
I think you overvalue the impact of the 3rd party and Homebrew space and dramatically overvalue the ink in a book that is guaranteed to sell like hotcakes.