Legal and Illegal Commas

By Geoffrey Pullum. One of the commenters on “Dumb Copy Editing Survives” last week said something that worried me. My topic was the contrast between sentences of the sort seen in [1a] and [1b] (I prefix [1b] with an asterisk to indicate that it is ungrammatical):

[1]	a.	We are none of us native or purebred.
	b.	*We are, none of us, native or purebred.

What the commenter said was: “If I read the erroneous version, I would have still taken away the exact same meaning. I’d just think there were too many commas.”
This worries me because it seems to miss the crucial distinction between contexts where comma use is a free choice and contexts where there is a firm rule. More...