Jisho.org Forum

Can you give an example of that? だ can't grammatically by put at the end of a question since it indicates a statement quite strongly. The only situation I could imagine would be something like:
"Why is he so popular?"
"Because he's funny?"
彼はなんでそんなに人気なの？
面白いんだ？

Though it sounds wrong to me and probably is, you would in all probability say 面白いから？

だ　can end questions like お前何してんだ？ or 日本って何だ？

Like in English, questions don't have to fit some template. As with "This is the biggest one you have?" or "You're leaving?", all there is to indicate that it's a question when spoken would be rising intonation. I think that Japanese is the same.

Posted By: louis

[p]だ　can end questions like お前何してんだ？ or 日本って何だ？[/p][p]Like in English, questions don't have to fit some template. As with "This is the biggest one you have?" or "You're leaving?", all there is to indicate that it's a question when spoken would be rising intonation. I think that Japanese is the same.[/p]

That is true... but I still think there's something special with the use of だ in those questions. It feels like pretty harsh questions, especially compaing
何してる？ to 何してんだ?

Hmm, then I guess だ would be used to end a question in informal situations? And in 'demanding questions'.

I agree with the above analysis of だ. Sounds harsh, like you'd be demanding an excuse or explanation.
In my imagination it would usually turn into だよ?! instead of just だ?! but that's not a rule or anything.

I'd add, I've heard just って? used as well (like as a short version of って何？) when quoting the speaker's word which was unknown to the listener.
In a formal situation it should probably be とは？ or something.

Silly Trivia:
In the Tochigi, Ibaraki, and Southern Fukushima dialect け replaces か :-D
I don't recommend using it, but it exists (like "ain't" or "I'mma" in English).