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.

and you want to fight ALONGSIDE them.
Game of Thrones Season 7, Episode 7

I will march them north to fight
ALONGSIDE you in the Great War.
Game of Thrones Season 7, Episode 7

I came north to fight ALONGSIDE you
Game of Thrones Season 8, Episode 4

Not burn him alive ALONGSIDE his son?
Game of Thrones Season 7, Episode 5

Will the Tyrell bannermen stand
ALONGSIDE a Dothraki horde
Game of Thrones Season 7, Episode 1