The best way to learn proper English is to read news report, and watch news on TV. Watching TV shows is a great way to learn casual English, slang words, understand culture reference and humor. If you have already watched these shows then you may recall the words used in the following dialogs.

Have no fear. The Lord Oaf of Highgarden
Game of Thrones Season 3, Episode 2

Mmm. No great
pleasure, believe me. A ponderous OAF.
Game of Thrones Season 3, Episode 2

His father was an OAF
as well. My husband, the late Lord Luthor.
Game of Thrones Season 3, Episode 2