Except if you're talking about Turkish, TDK dictates what words are real, how they're written, what they mean and other grammar and writing rules.

So why teach English at all? People could just make it all up theirself.

English dictionaries are also very much on the descriptive side of things as of late, especially compared to their counterparts among other languages.

Dunno how the tea totallers do things but here in burgerland we actually have sort of a minor annual event finding out the latest slang terms and grammars that have entered this year's edition of the webster dictionary, and which words have fallen out of significant use enough to be dropped from the book too.

I just like to point out that umami is a terrible word to import into English. Why? Because we already have a word for savory. It's savory. Worse, umami doesn't completely just mean savory. It also means meaty or deliciousness. In English, savory ≠ meaty, and deliciousness is subjective. The word just doesn't translate cleanly. So when anybody uses umami to describe savory food, all they're really doing is sounding like an imprecise, pretentious jackass.

Given our thoughts are largely impacted by the vocabulary we know, being able to come up with new words can be considered a super power!

But there is no single word in modern English for "the day after tomorrow" or "the day before yesterday".

In other languages, maybe. But not in English.

Fine, but I'm still not happy about 'performant'

Ok but "melty" isn't a real word and I'll die on this hill

even if it's a real word I hate it