I've noticed it a lot on these forums. A predominantly English/British forum yet people are unable to differentiate between: "you're" and "your" also: they're, there and their. "could have" when it should be "could have" I understand "could have" is possibly an easy one to get wrong as it sounds like that when you say it, well it sounds like "could've" which is the correct way to spell it.
Still, writing English correctly isn't a difficult task, although I do make mistakes so I'm not perfect.
It makes me wonder who taught them English in the first place.
Exactly, it doesn't take any more effort to write coherently.