Questions about Nintendo Mario Kart 8 Deluxe

You only need the subscription to play online. Offline, you don't need a subscription. You can play with four people on the TV/monitor. Or eight if each has a console and game.

Absolument.

Hello Yes, the game is installed with the switch system language. Greetings

The game can be started in English if you change the system language of your Switch to English or to another language (works with virtually any game) if there is no in-game language selection.

Hello Yes you can. Greetings