Japanese 291 - Denying permission with verb + ちゃいけない

In an earlier lesson you've learned that you can tell that things are forbidden using the て-form + はいけません.

This is a strict way to express that something must not be done, while at the same time it is formal.

In informal speech, we can say the same by adding 〜ちゃいけない to the て-form stem of a verb. The て-form stem of a verb is obtained by taking the て-form, and then removing the from the end.

If the て-form of a verb ends in , then we attach 〜じゃいけない instead of 〜ちゃいけない.