A game where you’re dropped into a foreign city (which primarily uses the language you’re trying to learn). You need to use clues and hints from various contexts to decipher what various things mean, what the people are talking about etc and ultimately try to achieve some kind of an end goal (rescue your hypothetical imprisoned family or something). Would be an immersive 3d experience.

Absolute game changer for language learning in my opinion, because it would (1) be very fun and deeply engaging, (2) allow you to just pick up important things. This link does a good demo (but the game they have is for an ancient language and not fully well developed): https://www.instagram.com/reel/CzKC2YhvoPO/

If people actually enjoy these games and learn well from them, schools might even be willing to pay to get access to them.

As the comments on the video demonstrate, there’s clearly a lot of demand for a game like this that is based on actual real-life languages. They’re hard to develop tho, but if done well there’s huge scope.