What is the interrogative informal form of 이다? Is it 냐/이냐? I wasn't able to find this answer anywhere so here I am asking ^^
There are three common ones.
- -(이)야? 네가 영훈이야? (Are you 영훈?)
- -(이)니? 네가 영훈이니? (same)
- -(이)냐? 네가 영훈이냐? (same)
-(이)야 is both an indicative and and interrogative form. -(이)니 and -(이)냐 are interrogative only. -(이)니? sounds more casual and friendly, while -(이)냐? may sound a bit rougher, like talking down. Females tend to prefer the former and males the latter.