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.

His birthday was moved to coincide
with the traditional PAGAN holiday...
The Big Bang Theory Season 3, Episode 11

Sire! How can we trust
the word of a PAGAN?
Vikings Season 1, Episode 7

No, because we don't celebrate
the ancient PAGAN festival of Saturnalia.
The Big Bang Theory Season 2, Episode 11