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.

If somebody says "Come in,"
I'm gonna FREAK out.
The Big Bang Theory Season 7, Episode 20

What, some tattooed speed FREAK?
Breaking Bad Season 2, Episode 11

...she unveiled the FREAK.
Game of Thrones Season 4, Episode 7
![[quietly]: Hey,
don\'t freak out,
[quietly]: Hey,
don\'t freak out,](data:image/png;base64,R0lGODlhAQABAAD/ACwAAAAAAQABAAACADs=)
[quietly]: Hey,
don't FREAK out,
The Big Bang Theory Season 12, Episode 7

No, it would just FREAK him out.
The Big Bang Theory Season 3, Episode 12