Prohibition in Japanese depending on level of formality


I have learnt two variants for prohibition: -ちゃだめ -ではいけません depending on the
level of formality…

But does an intermediate form of -じゃいけない or -ではいけない

exist as well?




Yes, all combinations are possible. Taking 見る as an example, you can say all
of the following (roughly in the descending order of formality):

  * 見てはいけません。
  * 見てはだめです。
  * 見てはいけない。
  * 見ちゃいけない。
  * 見ちゃだめ(だ(よ))。

だめです may look like a weird combination of a colloquial word and the polite
form, but it can happen when a teacher say "don't ..." to their students, for
example.




Yes, all combinations are possible. Taking 見る as an example, you can say all
of the following (roughly in the descending order of formality):

  * 見てはいけません。
  * 見てはだめです。
  * 見てはいけない。
  * 見ちゃいけない。
  * 見ちゃだめ(だ(よ))。

だめです may look like a weird combination of a colloquial word and the polite
form, but it can happen when a teacher say "don't ..." to their students, for
example.

