No Da Conjugations Help

[ZeRinku]

When you conjugate to simplify "no da"(the explaining tone) there is two ways to conjugate. One is where the Noun, adjective and verbs just have "nda" tacked on the end(besides plain non-past). For example 学生じゃないんだ (negative non-past). Then you have another way to conjugate where "no da" is conjugated itself. For examle the negative non-past of this form is 学生なんじゃない. So we have the negative non-past forms for both conjugations...

学生じゃないんだ

and

学生なんじゃない

Do these both mean the same things, and can I use any form I want? Do both conjugations mean the same thing and just has two ways of saying it? Or is there a difference in meaning?

[hatch_jp]

As you said, 学生じゃないんだ is a negative non-past. it means like "You are not a student, right?" or "You are not a student, are you" (when the subject is "you")
～じゃないんだ is used when you notice/realize something not true on the spot.


学生なんじゃない means "he must be a student", "I assume he is a student" , "I think he is a student" etc (when the subject is "he")
～なんじゃない is used for uncertain things.

[ZeRinku]

As you said, 学生じゃないんだ is a negative non-past. it means like "You are not a student, right?" or "You are not a student, are you" (when the subject is "you")
～じゃないんだ is used when you notice/realize something not true on the spot.


学生なんじゃない means "he must be a student", "I assume he is a student" , "I think he is a student" etc (when the subject is "he")
～なんじゃない is used for uncertain things.

For ～なんじゃない you said "he must be a student" don't you mean for this form "he must NOT be a student"?

[hatch_jp]

～なんじゃない means positive whereas ない is included.

Other translation is "He is a student, isn't he?"

[Psy]

In case that wasn't clear (hatch knows his language, of course, but I thought the last explanation was a little bit fuzzy), here's my attempt at pushing the nuance into English:

学生じゃないんだ -- he's not a student (being quite sure he isn't)
学生なんじゃない -- he is a student, isn't he? (thinking he is)

If you try emphasizing those words in English, I think the meanings will become clearer to you.