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.

It's time for a very special guest CALLER.
The Big Bang Theory Season 8, Episode 20

Thanks, CALLER. You know the movie
actually has a little bit of a cult following?
The Big Bang Theory Season 8, Episode 20

Need the location of an incoming CALLER.
Breaking Bad Season 5, Episode 14

Hello, CALLER. You are on with Penny and Wil
from Serial Ape-ist 2.
The Big Bang Theory Season 8, Episode 20

You know what?
That's not a flag question, next CALLER.
The Big Bang Theory Season 9, Episode 15