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.

We both know the PENALTY for that crime.
Game of Thrones Season 6, Episode 3

The PENALTY for desertion...
Game of Thrones Season 1, Episode 7

They were gonna charge us
a PENALTY.
Breaking Bad Season 2, Episode 1