てはいけない and てはならない
This page explains てはいけない and てはならない, two nearly identical phrases and
common sound variations and abbreviations.
てはいけない
Verb is not allowed
Verbてはいけない
Verbてform+はいけない, means doing the verb is prohibited. It is usually used by someone socially higher to someone socially lower, and is a prohibitive command. The prohibition can be legal, societal, or based on your opinion.
This is stronger than ないで +ください
Examples
- 読んではいけない — It’s not ok to read it. → You aren’t allowed to read it.
- 走ってはいけない – Its not ok to run. → You aren’t allowed to run.
てはならない
It’s not acceptable to do~
Verbてはならない
てはならない is the sister phrase to てはいけない and means essentially the same thing, but implies a rule or societal prohibition. It is more objective than てはいけない。You may use this for your own opinions, as long as they’re commonly accepted.
You only need to be aware of this phrase as it’s unlikely you’ll need to use it. (At this stage of Japanese).
Source (all Japanese/Chinese)
Source (all Japanese).
Examples
- 人をおどしてはならない。- It’s not acceptable to threaten people.
- 仕事をさぼってはならない – It’s not acceptable to skip work.
Variations
Polite Negative Form
いけない→いけません
ならない→なりません
いけない is a normal simple present negative tense verb. As such, You may use the ません forms of いけない and ならない, いけません and なりません。
Examples
- はしってはいけません。- Its not ok to run.
- いってはなりません。- It’s not acceptable to say it.
Sound Changes
Common Sound Changes
ては→ちゃ
では→じゃ
てはいけない has 2 common sound abbreviations in informal speech. These sound changes are really common and natural so they shouldn’t take too long to get used to.
Final note:
Do you remember じゃない？It was originally ではない that underwent a sound change.
Sound changes:
- ては→ちゃ ーちゃいけない.
- では→じゃーじゃいけない.
Additionally, you may also substitute the synonyms だめ or よくない for いけない。
Sound Change Examples
- 遊んではいけない →遊んじゃいけない – It’s not ok to play.
- 触れてはならない →触れちゃならない – It’s not acceptable to touch (something).
Synonym Substitution Examples
- 遊んではだめですよ。 – It’s bad to play.
- よんではよくないです。 – It’s not ok to read it.