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.

has been the core of every PEACEFUL,
prosperous reign we've ever known.
Game of Thrones Season 8, Episode 4

My people are not PEACEFUL.
Game of Thrones Season 8, Episode 2

It's PEACEFUL and deep.
The Big Bang Theory Season 10, Episode 13

My people are PEACEFUL.
Game of Thrones Season 8, Episode 2

It's actually kind of PEACEFUL.
The Big Bang Theory Season 12, Episode 12