New Super Mario Bros and Super Mario 64 DS came with a lot of great minigames. IIRC they take very little (no?) language, but I last played ~15 years ago. Extra great because of DS download play. (Peer-to-peer connection, no online services needed.)

Mario Kart is also a classic.

funnily enough, i already had those roms downloaded but yea!!! i thought of mario kart and tetris first

if you're playing on an actual DS, the ping pong minigame in WarioWare Touched is silly and fun for a bit. Gotta unlock it first though and it's the only multiplayer part of that game iirc.

i don't remember if i unlocked it on my copy but i'll try this!!!

it's cute because both players play using the same DS, it's just a timing game where you each hold it, one player uses L and one uses R to hit the ball. Surprisingly good fun :D

clubhouse games is pretty basic but it might be nice if your mum isnt a hardcore twitch gamer