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.

But it don't hurt to let 'em ROT a while longer.
Game of Thrones Season 2, Episode 8

to find beautiful corpses
before they ROT.
Game of Thrones Season 1, Episode 5

My father knew and he left me to ROT
at the Wall all the same.
Game of Thrones Season 1, Episode 3

Rot, you son of a bitch.
Breaking Bad Season 5, Episode 9

You will live
to watch your daughter ROT.
Game of Thrones Season 7, Episode 3