Inversion

The point

After a negative or limiting opener such as never, not only, or little, the auxiliary comes before the subject. Were we to wait is the inverted form of if we were to wait. The meaning does not change. The order does.

Form and use

After a negative or limiting opener, the auxiliary comes before the subject. The rest of the sentence keeps normal order. This is formal, but the pattern is fixed. If there is no auxiliary, use do, does, or did.

Openers that force inversion: Never have we delayed a warning. Rarely does she miss a date. Seldom had they seen such a gap. Little did he know the risk. Not only did she flag it, but she moved it. No sooner had we sent it than they replied. Hardly had I sat down when the call came. Under no circumstances should you share the file. Not until Monday did the note arrive. Not until takes inversion in the main clause, not in the until-clause.

Conditionals can drop if and invert. Were I the editor, I would send it. Had I known, I would have waited. Should you need help, call me. Were I replaces if I were. Had I known replaces if I had known. Should you need replaces if you should need. Do not add if back in, and do not use a normal subject-verb order after these openers.

Without the opener, do not invert. We have never delayed a warning is the ordinary sentence. Never we have delayed is missing the auxiliary move. Not only she flagged it is also wrong: not only needs did, or another auxiliary, before the subject. Keep than after no sooner, and when after hardly.

Don't translate it like this

Never at the front forces the auxiliary in front of the subject.

Short examples