More "do you say this?"

[pne]

Again from Language Log, I came across an article comparing "let's not", "don't let's" and "let's don't", and quoting The Columbia Guide to Standard American English as saying that all three are standard.

I've only come across the first of those, and would have thought the second and third are substandard, though again, this may merely be an Americanism.

[Poll #753767]