This week we're learning commands (V２stem＋なさい) and admonishments (Vてはいけません). Although 501 Japanese Verbs lists the negative equivalent of なさい as なさるな, we aren't being taught that. Maybe it's archaic, or literary, or too impolite.

However, I really like the form (Vてはいけません) because it reminds me of an expression in English that became popular in the 1990s "Don't go there." People usually said it in a conversation to mean "Don't broach that subject." that is, don't open up the subject for discussion because talking about it will just cause more problems. "Broach" means to pierce or to open; it also means to turn a boat so that it is broadside to the waves--a dangerous position to be in, somewhere you don't want to go.

いけません means "can't go". It is the potential form of 行く「いく」. In English "can't" can refer to to either internal (I am unable to) or external (you are not allowed to) constraints. Strictly speaking, a negative command in English should be "will not", "shall not", or "must not". You'll find those forms in legal documents and literature. In casual conversation people say, "You can't do that!" "Oh yes I can. And you can't stop me!"

The Japanese expression we've learned for admonishment (Oh! You mustn't do that.) is Vてはいけません。For example, お酒をのんではいけません。means "You mustn't drink alcohol." But literally it means "As for drinking alcohol, you can't go there." I love it! In English we would say, "...don't even think it." which means "Don't do it. Don't even think about doing it."

We learned some other expressions to use as admonishments, too.

• Vてはいけません。(As for doing V, you can't go there.)
• Vてはなりません。(As for doing V, it must not be, it must not become so. This is like the English expression, "...make sure it doesn't happen.")
• Vてはだめです。(As for doing V, you can't.)
• Vてはこまります。(As for doing V, that's a problem.)

These are all great expressions and I love them. But do you use them? Our book expresses the equivalent in English with the word "mustn't" which is the contraction of must not. I can't remember the last time I heard anyone say "mustn't". Usually people (well, Americans) are going to say "You can't..." or "Don't..." which our book translates as "V3 + な". For example, 行くな、飲むな、食べるな。(Don't go! Don't drink! Don't eat!)

What expression do you usually use in Japanese when you are telling someone that they "mustn't" do something?" I assume your answer depends on whether your a man or a woman, how old you are, and who you are talking to.