I just watched a video on this topic. I've been learning Japanese for roughly 2 years now and it still confuses me. I need some clarifications. What I've been able to establish is:
- don't use の in genuine questions because it comes off... weird? It shows a surprise. You'd rather say なにしてる？ rather than なにしてるの？ and that applies basically to any question.
- don't use んだ？in questions if you're a woman. Sounds rough. Use の or んですか
- use の and んだ/です to express "because..." without actually saying the actual word から. Usually in answer to なんで/どうした
3.5 When you ask questions with なんで/どうした add の/んですか？to sound more natural. Don't use んだ？if you're a female.
- んだ + けど (ですが） sets up the context for what we really want our speaker to pay attention to. The second sentences is more important. Can be translated as "and." You can ask questions with it too.
- んだ/です can work as a new topic starter. "So...I did this or that" you want to be questioned about it/talk about it/brag about it even?
- Don't state facts with んだ/です "I bought a new car." Simple fact. Nothing interesting to it.
- logical assumptions. "oh, I see, so.. you're an anime fan" (The person keeps talking about it hence my assumption)
Am I correct? Is there anything else to it? I'm pretty sure it all hinges on context (like pretty much everything). Also, is the tone of my voice also important here?
One more question. I've encountered ゲームを買うんじゃなかった translated as "I shouldn't have bought the game"
Is んじゃなかった a negation of んです？it really confuses me.
Wouldn't it mean "It was because I didn't buy the game"