More negatives with なくて, ないで, ず and ずに

We briefly discussed the difference between なくて and ないで in Lesson 11. Let's dig a bit deeper into it.

When we make a verb or い adjective into the なくて form, this behaves like a usual て conjunctive form (“do X, and…”). It is common in this usage to imply some cause -> effect sequence (“I didn’t do X, and that is why Y happened”) although not strictly required.

お役に立てなくてすみません。  
I am sorry I was not helpful (lit. “I was not helpful and so I am sorry”)

We can also make the negative with ないで instead, however in contrast with なくて, this usage often implies a manner or state in which the following action is being done. You can think of the statement before ないで to become an “adverb” to the statement after it.

もしかして、食べないで待っていたのか
Perhaps… did you wait without eating?

ノックもしないで部屋に入る。
To enter the room without even knocking.

There is another way we can use なくて and ないで, and that is using the verb forms 〜ず and 〜ずに. ず is an archaic conjugation of the negative auxiliary verb ぬ, but you don’t really need to know this. Just remember that 〜ず is almost a 1:1 replacement to なくて (or in some cases なく), and 〜ずに is a replacement of ないで. In some cases, 〜ず alone (without に) can also be used as ないで (Yay, Japanese!).

お役に立てず、申し訳ございません。
I am sorry I was not helpful

何も食べずに眠ってしまった。
He fell asleep without eating anything

ず and ずに are more formal and stiff-sounding than their なくて and ないで counterparts and are mostly used in literary stuff. However you will still hear plenty of ずに in spoken language too and they show up a lot in common phrases and expressions.