Japanese Grammar lesson on how to say "You shouldn't have done it!" in Japanese.

JPPGG #102
Japanese Plug and Play Ghetto Grammar #102
By Makurasuki Sensei

The kanji to the right represents the English word sweat. One of its readings is Ase. The verb to sweat is ase o kaku, and that is what you do when you do something that you later regret doing.

The following grammar constructions equivalent English expression is "I shouldn't have done it...", (Where done it, is replaced by verb{p.f.}) or near literally as, "It wasn't meant to be" or literally as an emphatic "didn't verb".

Yet those translations can only approximate what is meant by the JA NAKATTA portion of the grammar construction. In conventional Japanese grammar, a verb in plain form can be emphasized by adding no desu.

kuru no desu - this phrase means more than just, "I come", but more like an emphasized "I AM COMING YO!" "FOR SURE!" That is the nuance of adding no desu to a plain form verb. The no part of the no desu is usually contracted so that in spoken Japanese, no, becomes the morpheme n. JA is the contraction of DEWA, or its own formal form. Getting a handle on this one simple substitution marks a learning phase in the acquisition of Japanese.

Remember!

JA is simply DEWA.
JA = DEWA

JA NAI = DEWA ARIMASEN
etc. = DEWA NAI DESU
JA NAKATTA = DEWA NAKATTA or
= DEWA ARIMASEN DESHITA ETC.

In formal polite Japanese, DEWA is used instead of JA for all negative verb forms*. So instead of DEWA ARIMASEN, you would have JA ARIMASEN, and instead of DEWA NAI you would have JA NAI. For DEWA NAKATTA, you would have JA NAKATTA.

Please see the JPPGG Verb Boxes.