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.

How many Starks they got to BEHEAD
before you figure it out?
Game of Thrones Season 4, Episode 3

And I came here knowing that
you could have your men BEHEAD me
Game of Thrones Season 7, Episode 5

I have many guards who'd
happily imprison him or BEHEAD him
Game of Thrones Season 7, Episode 6

Oh, I can't BEHEAD you.
Game of Thrones Season 5, Episode 9

Of course,
they will BEHEAD you as a deserter.
Game of Thrones Season 1, Episode 1