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.

Oh, hey, on a RELATED subject...
The Big Bang Theory Season 3, Episode 6

Now, on a RELATED point,
you're going down, punk.
The Big Bang Theory Season 10, Episode 19

did you ever do anything
remotely RELATED to combat?
Game of Thrones Season 4, Episode 5

Drug RELATED, you said?
MERKERT: lt's a good possibility.
Breaking Bad Season 4, Episode 8

All right.
Is my pole flag RELATED?
The Big Bang Theory Season 9, Episode 15