All I'm learning from this thread is that no one can tell any consistent signs.

Poor grammar/orthography

Vertical filming, putting music into videos when you could just use silence

slang mostly, I mod a strictly 18+ space and recently someone used the word "skeet", and would you believe it, they were a minor

"skibidi" "rizz" "sus"

Extensive use of emojis and abbreviations is a good indicator.

"im 9 btw"

Excessive swearing, as if they just learned how to say “fuck”.

Not that any damn amount of fucking swearing means they are are a young fucker, but you can fucking tell when you read that shit and they manage nine goddamn swear words in one fucking sentence you know they’re a young bitch who aren’t allowed to swear any other damn time.

ask if they remember these

Crypto bros who follow ultra distorted stoicism (the only good philosophy is the ones made when slavery was normalised) that believe everyone else is unaware of what very basic knowledge they world they just learned that day.

Not sure if it's the case anymore, but strong opinions were matched with EQUALLY STRONG STYLISTIC CHOICE!!!!!!!, often coupled with poor grammar/spelling, and a tendency to lean more towards rehashing the same opinion rather than making a rational argument for it.

Quick to call other people kids as an insult.

Writing in short form where a lengthier reply would work better and when confronted with such a reply some form of "not reading all that" or other thought terminating clichés.

I've found that as arbitrary as it is - the ability to read a lot of information works pretty well as a mark of mental maturity. Also links to Twitter or Tiktok as discussion points. No one over the age of 19 browses TikTok lol.

When they start calling people "jr" or implying anyone who disagrees with them is too young to understand.

Probably just internet slang and the skull emoji. That and poor grammar are (possible) indicators.

This one has been easy for me lately: They spell 'lose' as 'loose'.

They’re the ones who are not obsessing over children’s toys or saying “adulting is difficult!”.

skibidi toilet

"Arguing" by listing a long list of fallacies that they don't really even understand.

Fallacy fallacy!

Unfaltering loyalty to the Chinese Communist Party