I’ve seen “let alone” used on Lemmy a good number of times now and, at least when I noticed it, it was always used incorrectly. It’s come to a point where I still feel like I’m being gaslit even after looking up examples, just because of the sheer amount of times I’ve seen it used outright wrong.
What I’m talking about is people switching up the first and last part. In “X, let alone Y” Y is supposed to be the more extreme case, the one that is less likely to happen, or could only happen if X also did first.
The correct usage: “That spaghetti must have been months old. I did not even open the box, let alone eat it.”
How I see it used constantly: “That spaghetti must have been months old. I did not eat it, let alone open the box.”
Other wrong usage: “Nobody checks out books anymore, let alone visits the library.”
Why does this bug me so much? I don’t know. One reason I came up with is that it’s boring. The “wrong” way the excitement always ramps down with the second sentence, so why even include it?
I am prepared to be shouted down for still somehow being incorrect about this. Do your worst. At least I’ll know I keep shifting between dimensions where “let alone” is always used differently or something.
“not to mention” and “let alone” are both typically used with the more difficult or unpleasant things after the phrase. The main difference is that “not to mention” is usually used to bring something new into the conversation or to imply that the thing you’re mentioning needs a whole separate conversation.
“Let alone” is a way to add emphasis when denying something. Usually phrased like “I didn’t even X, let alone Y.” Y being the thing you want to deny, X being some first step toward Y or just something related that isn’t as bad as Y.
Some examples:
“Did you kill Dave?” “I didn’t touch him, let alone kill him”
“Can you walk?” “I can’t stand, let alone walk.”
The first part doesn’t even need to be a complete denial as long as it implies the second part is impossible:
“Can you run?” “I can barely stand, let alone run.”