This is a 2-in-1 question, I suppose. I type the way I do. I’ve always typed this way, but I’ve noticed when interacting with people (not on here) that people always think I’m far older than 19. They think I’m in my forties or fifties.
Also, I tend to type using full stops, which people may think are rude. When I’m typing a full sentence, though, I end it with a period. If I say, “He’s being an asshole,” (with a period), I mean that as a fact, not out of anger. It just happens to be ended with a period since it’s a sentence.
The obvious examples are people typing in Scots or AAVE but that’s more just phonetic transcription of existing language.
https://youtu.be/SDPasRas5u0
This video is ten years old so the examples are outdated but the idea is sound.
Scots is its own language with its own writing system, people have been writing in Scots for centuries before the internet and it’s not just colloquial. Scottish English is seperate, being an actual dialect, but there is an English-Scots dialect continuum so finding the exact difference is hard