(잃고 있는데 => 읽고 있는데; 몰아요 => 몰라요.) 언어 is "language", 파괴 destruction, and 자 a person or "agent" who effects something. So 언어파괴자 literally means "language destroyer" but that sounds a bit extreme perhaps. I don't know if there's another popular word for this in English - "language debaser" maybe? It seems there is a growing problem of this 언어파괴자 in some parts of the internet culture. With Korean for example, there is a worrisome trend of people casually ignoring and flouting the established language rules. Even worse, there are sites and groups of people who intentionally violate the rules and conventions, usually for fun but also as part of showing their political agenda and what not.